mathhalf.c
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上传日期:2021-02-19
资源大小:1051k
文件大小:58k
源码类别:
语音压缩
开发平台:
C/C++
- /***************************************************************************
- *
- * File Name: mathhalf.c
- *
- * Purpose: Contains functions which implement the primitive
- * arithmetic operations.
- *
- * The functions in this file are listed below. Some of them are
- * defined in terms of other basic operations. One of the
- * routines, saturate() is static. This is not a basic
- * operation, and is not reference outside the scope of this
- * file.
- *
- *
- * abs_s()
- * add()
- * divide_s()
- * extract_h()
- * extract_l()
- * L_abs()
- * L_add()
- * L_deposit_h()
- * L_deposit_l()
- * L_mac()
- * L_msu()
- * L_mult()
- * L_negate()
- * L_shift_r()
- * L_shl()
- * L_shr()
- * L_sub()
- * mac_r()
- * msu_r()
- * mult()
- * mult_r()
- * negate()
- * norm_l()
- * norm_s()
- * round()
- * saturate()
- * shift_r()
- * shl()
- * shr()
- * sub()
- *
- **************************************************************************/
- #include "typedefs.h"
- #include "mathhalf.h"
- #include "mathdp31.h"
- /***************************************************************************
- *
- * FUNCTION NAME: saturate
- *
- * PURPOSE:
- *
- * Limit the 32 bit input to the range of a 16 bit word.
- *
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * KEYWORDS: saturation, limiting, limit, saturate, 16 bits
- *
- *************************************************************************/
- static Shortword saturate(Longword L_var1)
- {
- Shortword swOut;
- extern int saturation;
- if (L_var1 > SW_MAX) {
- swOut = SW_MAX;
- saturation = saturation + 1;
- }
- else if (L_var1 < SW_MIN) {
- swOut = SW_MIN;
- saturation = saturation + 1;
- }
- else {
- swOut = (Shortword) L_var1; /* automatic type conversion */
- }
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: divide_s
- *
- * PURPOSE:
- *
- * Divide var1 by var2. Note that both must be positive, and
- * var1 >= var2. The output is set to 0 if invalid input is
- * provided.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * In the case where var1==var2 the function returns 0x7fff. The output
- * is undefined for invalid inputs. This implementation returns zero
- * and issues a warning via stdio if invalid input is presented.
- *
- * KEYWORDS: divide
- *
- *************************************************************************/
- /* Shortword divide_s(Shortword var1, Shortword var2) */
- /* { */
- /* Longword L_div; */
- /* Shortword swOut; */
- /* // extern int complexity;mark del */
- /* // int old_complexity;mark del */
- /* */
- /* // old_complexity = complexity;Longword */
- /* if (var1 < 0 || var2 < 0 || var1 > var2) { */
- /* undefined output for invalid input into divide_s */
- /* return ((Shortword)0); */
- /* } */
- /* */
- /* if (var1 == var2) */
- /* return ((Shortword)0x7fff); */
- /* */
- /* L_div = ((0x00008000L * (Longword) var1) / (Longword) var2); */
- /* swOut = saturate(L_div); */
- /* // complexity = old_complexity + 18;mark del */
- /* return (swOut); */
- /* } */
- /***************************************************************************
- *
- * FUNCTION NAME: L_deposit_l
- *
- * PURPOSE:
- *
- * Put the 16 bit input into the 16 LSB's of the output Longword with
- * sign extension i.e. the top 16 bits are set to either 0 or 0xffff.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0xffff 8000 <= L_var1 <= 0x0000 7fff.
- *
- * KEYWORDS: deposit, assign
- *
- *************************************************************************/
- Longword L_deposit_l(Shortword var1)
- {
- Longword L_Out;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_Out = var1;
- // complexity = old_complexity + 2;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_deposit_h
- *
- * PURPOSE:
- *
- * Put the 16 bit input into the 16 MSB's of the output Longword. The
- * LS 16 bits are zeroed.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff 0000.
- *
- *
- * KEYWORDS: deposit, assign, fractional assign
- *
- *************************************************************************/
- Longword L_deposit_h(Shortword var1)
- {
- Longword L_var2;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_var2 = (Longword) var1 << 16;
- // complexity = old_complexity + 2;mark del
- return (L_var2);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: extract_l
- *
- * PURPOSE:
- *
- * Extract the 16 LS bits of a 32 bit Longword. Return the 16 bit
- * number as a Shortword. The upper portion of the input Longword
- * has no impact whatsoever on the output.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- *
- * KEYWORDS: extract, assign
- *
- *************************************************************************/
- Shortword extract_l(Longword L_var1)
- {
- Shortword var2;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- var2 = (Shortword) (0x0000ffffL & L_var1);
- // complexity = old_complexity + 1;mark del
- return (var2);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: extract_h
- *
- * PURPOSE:
- *
- * Extract the 16 MS bits of a 32 bit Longword. Return the 16 bit
- * number as a Shortword. This is used as a "truncation" of a fractional
- * number.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * KEYWORDS: assign, truncate
- *
- *************************************************************************/
- Shortword extract_h(Longword L_var1)
- {
- Shortword var2;
- // extern int complexity; mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- var2 = (Shortword) (0x0000ffffL & (L_var1 >> 16));
- // complexity = old_complexity + 1;mark del
- return (var2);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: round
- *
- * PURPOSE:
- *
- * Round the 32 bit Longword into a 16 bit shortword with saturation.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Perform a two's complement round on the input Longword with
- * saturation.
- *
- * This is equivalent to adding 0x0000 8000 to the input. The
- * result may overflow due to the add. If so, the result is
- * saturated. The 32 bit rounded number is then shifted down
- * 16 bits and returned as a Shortword.
- *
- *
- * KEYWORDS: round
- *
- *************************************************************************/
- Shortword round(Longword L_var1)
- {
- Longword L_Prod;
- Shortword var2;
- // extern int complexity; mark del
- // int old_complexity; mark del
- // old_complexity = complexity; mark del
- L_Prod = L_add(L_var1, 0x00008000L); /* round MSP */
- var2 = extract_h(L_Prod);
- // complexity = old_complexity + 1; mark del
- return (var2);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: negate
- *
- * PURPOSE:
- *
- * Negate the 16 bit input. 0x8000's negated value is 0x7fff.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8001 <= swOut <= 0x0000 7fff.
- *
- * KEYWORDS: negate, negative, invert
- *
- *************************************************************************/
- /* Shortword negate(Shortword var1) */
- /* { */
- /* Shortword swOut; */
- /* // extern int complexity;mark del */
- /* extern int saturation; */
- /* // int old_complexity;mark del */
- /* */
- /* // old_complexity = complexity;mark del */
- /* if (var1 == SW_MIN) { */
- /* saturation = saturation + 1; */
- /* swOut = SW_MAX; */
- /* } */
- /* else { */
- /* swOut = -var1; */
- /* } */
- /* // complexity = old_complexity + 1;mark del */
- /* return (swOut); */
- /* } */
- /***************************************************************************
- *
- * FUNCTION NAME: L_negate
- *
- * PURPOSE:
- *
- * Negate the 32 bit input. 0x8000 0000's negated value is
- * 0x7fff ffff.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0001 <= L_var1 <= 0x7fff ffff.
- *
- * KEYWORDS: negate, negative
- *
- *************************************************************************/
- Longword L_negate(Longword L_var1)
- {
- Longword L_Out;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (L_var1 == LW_MIN) {
- saturation = saturation + 1;
- L_Out = LW_MAX;
- }
- else {
- L_Out = -L_var1;
- }
- // complexity = old_complexity + 2;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: add
- *
- * PURPOSE:
- *
- * Perform the addition of the two 16 bit input variable with
- * saturation.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Perform the addition of the two 16 bit input variable with
- * saturation.
- *
- * swOut = var1 + var2
- *
- * swOut is set to 0x7fff if the operation results in an
- * overflow. swOut is set to 0x8000 if the operation results
- * in an underflow.
- *
- * KEYWORDS: add, addition
- *
- *************************************************************************/
- Shortword add(Shortword var1, Shortword var2)
- {
- Longword L_sum;
- Shortword swOut;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_sum = (Longword) var1 + var2;
- swOut = saturate(L_sum);
- // complexity = old_complexity + 1;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_add
- *
- * PURPOSE:
- *
- * Perform the addition of the two 32 bit input variables with
- * saturation.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- * L_var2
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var2 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * IMPLEMENTATION:
- *
- * Perform the addition of the two 32 bit input variables with
- * saturation.
- *
- * L_Out = L_var1 + L_var2
- *
- * L_Out is set to 0x7fff ffff if the operation results in an
- * overflow. L_Out is set to 0x8000 0000 if the operation
- * results in an underflow.
- *
- * KEYWORDS: add, addition
- *
- *************************************************************************/
- Longword L_add(Longword L_var1, Longword L_var2)
- {
- Longword L_Sum,
- L_SumLow,
- L_SumHigh;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_Sum = L_var1 + L_var2;
- if ((L_var1 > 0 && L_var2 > 0) || (L_var1 < 0 && L_var2 < 0)) {
- /* an overflow is possible */
- L_SumLow = (L_var1 & (Longword)0xffff) + (L_var2 & (Longword)0xffff);
- L_SumHigh = ((L_var1 >> 16) & (Longword)0xffff) + ((L_var2 >> 16) & (Longword)0xffff);
- if (L_SumLow & (Longword)0x10000) {
- /* carry into high word is set */
- L_SumHigh += 1;
- }
- /* update sum only if there is an overflow or underflow */
- /*------------------------------------------------------*/
- if (((Longword)0x10000 & L_SumHigh) && !((Longword)0x8000 & L_SumHigh)) {
- saturation = saturation + 1;
- L_Sum = LW_MIN; /* underflow */
- }
- else if (!((Longword)0x10000 & L_SumHigh) && ((Longword)0x8000 & L_SumHigh)) {
- saturation = saturation + 1;
- L_Sum = LW_MAX; /* overflow */
- }
- }
- // complexity = old_complexity + 2;mark del
- return (L_Sum);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: sub
- *
- * PURPOSE:
- *
- * Perform the subtraction of the two 16 bit input variable with
- * saturation.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Perform the subtraction of the two 16 bit input variable with
- * saturation.
- *
- * swOut = var1 - var2
- *
- * swOut is set to 0x7fff if the operation results in an
- * overflow. swOut is set to 0x8000 if the operation results
- * in an underflow.
- *
- * KEYWORDS: sub, subtraction
- *
- *************************************************************************/
- /* Shortword sub(Shortword var1, Shortword var2) */
- /* { */
- /* Longword L_diff; */
- /* Shortword swOut; */
- /* // extern int complexity;mark del */
- /* // int old_complexity;mark del */
- /* */
- /* // old_complexity = complexity;mark del */
- /* L_diff = (Longword) var1 - var2; */
- /* swOut = saturate(L_diff); */
- /* */
- /* // complexity = old_complexity + 1;mark del */
- /* return (swOut); */
- /* } */
- /***************************************************************************
- *
- * FUNCTION NAME: L_sub
- *
- * PURPOSE:
- *
- * Perform the subtraction of the two 32 bit input variables with
- * saturation.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- * L_var2
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var2 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * IMPLEMENTATION:
- *
- * Perform the subtraction of the two 32 bit input variables with
- * saturation.
- *
- * L_Out = L_var1 - L_var2
- *
- * L_Out is set to 0x7fff ffff if the operation results in an
- * overflow. L_Out is set to 0x8000 0000 if the operation
- * results in an underflow.
- *
- * KEYWORDS: sub, subtraction
- *
- *************************************************************************/
- Longword L_sub(Longword L_var1, Longword L_var2)
- {
- Longword L_Sum;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- /* check for overflow */
- if ((L_var1 > 0 && L_var2 < 0) || (L_var1 < 0 && L_var2 > 0)) {
- if (L_var2 == LW_MIN) {
- L_Sum = L_add(L_var1, LW_MAX);
- L_Sum = L_add(L_Sum, 1);
- }
- else
- L_Sum = L_add(L_var1, -L_var2);
- }
- else { /* no overflow possible */
- L_Sum = L_var1 - L_var2;
- }
- // complexity = old_complexity + 2;mark del
- return (L_Sum);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: shr
- *
- * PURPOSE:
- *
- * Arithmetic shift right (or left).
- * Arithmetically shift the input right by var2. If var2 is
- * negative then an arithmetic shift left (shl) of var1 by
- * -var2 is performed.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Arithmetically shift the input right by var2. This
- * operation maintains the sign of the input number. If var2 is
- * negative then an arithmetic shift left (shl) of var1 by
- * -var2 is performed. See description of shl for details.
- *
- * Equivalent to the Full-Rate GSM ">> n" operation. Note that
- * ANSI-C does not guarantee operation of the C ">>" or "<<"
- * operator for negative numbers.
- *
- * KEYWORDS: shift, arithmetic shift right,
- *
- *************************************************************************/
- Shortword shr(Shortword var1, Shortword var2)
- {
- Shortword swMask,
- swOut;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var2 == 0 || var1 == 0)
- swOut = var1;
- else if (var2 < 0) {
- /* perform an arithmetic left shift */
- /*----------------------------------*/
- if (var2 <= -15)
- {
- swOut = (var1 > 0) ? SW_MAX : SW_MIN; /* saturate */
- saturation = saturation + 1;
- }
- else
- swOut = shl(var1, (Shortword)-var2);
- }
- else {
- /* positive shift count */
- /*----------------------*/
- if (var2 >= 15)
- swOut = (var1 < 0) ? (Shortword) 0xffff : 0x0;
- else {
- /* take care of sign extension */
- /*-----------------------------*/
- swMask = 0;
- if (var1 < 0) {
- swMask = ~swMask << (16 - var2);
- }
- var1 >>= var2;
- swOut = swMask | var1;
- }
- }
- // complexity = old_complexity + 1;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: shl
- *
- * PURPOSE:
- *
- * Arithmetically shift the input left by var2.
- *
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * If Arithmetically shift the input left by var2. If var2 is
- * negative then an arithmetic shift right (shr) of var1 by
- * -var2 is performed. See description of shr for details.
- * When an arithmetic shift left is performed the var2 LS bits
- * are zero filled.
- *
- * The only exception is if the left shift causes an overflow
- * or underflow. In this case the LS bits are not modified.
- * The number returned is 0x8000 in the case of an underflow or
- * 0x7fff in the case of an overflow.
- *
- * The shl is equivalent to the Full-Rate GSM "<< n" operation.
- * Note that ANSI-C does not guarantee operation of the C ">>"
- * or "<<" operator for negative numbers - it is not specified
- * whether this shift is an arithmetic or logical shift.
- *
- * KEYWORDS: asl, arithmetic shift left, shift
- *
- *************************************************************************/
- Shortword shl(Shortword var1, Shortword var2)
- {
- Shortword swOut;
- Longword L_Out;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var2 == 0 || var1 == 0) {
- swOut = var1;
- }
- else if (var2 < 0) {
- /* perform a right shift */
- /*-----------------------*/
- if (var2 <= -15)
- swOut = (var1 < 0) ? (Shortword) 0xffff : 0x0;
- else
- swOut = shr(var1, (Shortword)-var2);
- }
- else {
- /* var2 > 0 */
- if (var2 >= 15) {
- swOut = (var1 > 0) ? SW_MAX : SW_MIN; /* saturate */
- saturation = saturation + 1;
- }
- else {
- L_Out = (Longword) var1 *(1 << var2);
- swOut = (Shortword) L_Out; /* copy low portion to swOut,
- * overflow could have hpnd */
- if (swOut != L_Out) {
- /* overflow */
- swOut = (var1 > 0) ? SW_MAX : SW_MIN; /* saturate */
- saturation = saturation + 1;
- }
- }
- }
- // complexity = old_complexity + 1;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_shr
- *
- * PURPOSE:
- *
- * Arithmetic shift right (or left).
- * Arithmetically shift the input right by var2. If var2 is
- * negative then an arithmetic shift left (shl) of var1 by
- * -var2 is performed.
- *
- * INPUTS:
- *
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- *
- * IMPLEMENTATION:
- *
- * Arithmetically shift the input right by var2. This
- * operation maintains the sign of the input number. If var2 is
- * negative then an arithmetic shift left (shl) of L_var1 by
- * -var2 is performed. See description of L_shl for details.
- *
- * The input is a 32 bit number, as is the output.
- *
- * Equivalent to the Full-Rate GSM ">> n" operation. Note that
- * ANSI-C does not guarantee operation of the C ">>" or "<<"
- * operator for negative numbers.
- *
- * KEYWORDS: shift, arithmetic shift right,
- *
- *************************************************************************/
- Longword L_shr(Longword L_var1, Shortword var2)
- {
- Longword L_Mask,
- L_Out;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var2 == 0 || L_var1 == 0) {
- L_Out = L_var1;
- }
- else if (var2 < 0) {
- /* perform a left shift */
- /*----------------------*/
- if (var2 <= -31) {
- L_Out = (L_var1 > 0) ? LW_MAX : LW_MIN; /* saturate */
- saturation = saturation + 1;
- }
- else
- L_Out = L_shl(L_var1, (Shortword)-var2);
- }
- else {
- if (var2 >= 31)
- L_Out = (L_var1 > 0) ? 0 : 0xffffffffL;
- else {
- L_Mask = 0;
- if (L_var1 < 0) {
- L_Mask = ~L_Mask << (32 - var2);
- }
- L_var1 >>= var2;
- L_Out = L_Mask | L_var1;
- }
- }
- // complexity = old_complexity + 2;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_shl
- *
- * PURPOSE:
- *
- * Arithmetic shift left (or right).
- * Arithmetically shift the input left by var2. If var2 is
- * negative then an arithmetic shift right (L_shr) of L_var1 by
- * -var2 is performed.
- *
- * INPUTS:
- *
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- *
- * IMPLEMENTATION:
- *
- * Arithmetically shift the 32 bit input left by var2. This
- * operation maintains the sign of the input number. If var2 is
- * negative then an arithmetic shift right (L_shr) of L_var1 by
- * -var2 is performed. See description of L_shr for details.
- *
- * Equivalent to the Full-Rate GSM ">> n" operation. Note that
- * ANSI-C does not guarantee operation of the C ">>" or "<<"
- * operator for negative numbers.
- *
- * KEYWORDS: shift, arithmetic shift left,
- *
- *************************************************************************/
- Longword L_shl(Longword L_var1, Shortword var2)
- {
- Longword L_Mask,
- L_Out=0;
- int i,
- iOverflow = 0;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var2 == 0 || L_var1 == 0) {
- L_Out = L_var1;
- }
- else if (var2 < 0) {
- if (var2 <= -31)
- L_Out = (L_var1 > 0) ? 0 : 0xffffffffL;
- else
- L_Out = L_shr(L_var1, (Shortword)-var2);
- }
- else {
- if (var2 >= 31)
- iOverflow = 1;
- else {
- if (L_var1 < 0)
- L_Mask = LW_SIGN; /* sign bit mask */
- else
- L_Mask = 0x0;
- L_Out = L_var1;
- for (i = 0; i < var2 && !iOverflow; i++) {
- /* check the sign bit */
- L_Out = (L_Out & 0x7fffffffL) << 1;
- if ((L_Mask ^ L_Out) & LW_SIGN)
- iOverflow = 1;
- }
- }
- if (iOverflow) {
- L_Out = (L_var1 > 0) ? LW_MAX : LW_MIN; /* saturate */
- saturation = saturation + 1;
- }
- }
- // complexity = old_complexity + 2;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: shift_r
- *
- * PURPOSE:
- *
- * Shift and round. Perform a shift right. After shifting, use
- * the last bit shifted out of the LSB to round the result up
- * or down.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- *
- * IMPLEMENTATION:
- *
- * Shift and round. Perform a shift right. After shifting, use
- * the last bit shifted out of the LSB to round the result up
- * or down.
- *
- * If var2 is positive perform a arithmetic left shift
- * with saturation (see shl() above).
- *
- * If var2 is zero simply return var1.
- *
- * If var2 is negative perform a arithmetic right shift (shr)
- * of var1 by (-var2)+1. Add the LS bit of the result to var1
- * shifted right (shr) by -var2.
- *
- * Note that there is no constraint on var2, so if var2 is
- * -0xffff 8000 then -var2 is 0x0000 8000, not 0x0000 7fff.
- * This is the reason the shl function is used.
- *
- *
- * KEYWORDS:
- *
- *************************************************************************/
- Shortword shift_r(Shortword var1, Shortword var2)
- {
- Shortword swOut,
- swRnd;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var2 >= 0)
- swOut = shl(var1, var2);
- else {
- /* right shift */
- if (var2 < -15) {
- swOut = 0;
- }
- else {
- swRnd = (Shortword)(shl(var1, (Shortword)(var2 + 1)) & (Shortword)0x1);
- swOut = add(shl(var1, var2), swRnd);
- }
- }
- // complexity = old_complexity + 2;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_shift_r
- *
- * PURPOSE:
- *
- * Shift and round. Perform a shift right. After shifting, use
- * the last bit shifted out of the LSB to round the result up
- * or down.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- *
- * IMPLEMENTATION:
- *
- * Shift and round. Perform a shift right. After shifting, use
- * the last bit shifted out of the LSB to round the result up
- * or down. This is just like shift_r above except that the
- * input/output is 32 bits as opposed to 16.
- *
- * if var2 is positve perform a arithmetic left shift
- * with saturation (see L_shl() above).
- *
- * If var2 is zero simply return L_var1.
- *
- * If var2 is negative perform a arithmetic right shift (L_shr)
- * of L_var1 by (-var2)+1. Add the LS bit of the result to
- * L_var1 shifted right (L_shr) by -var2.
- *
- * Note that there is no constraint on var2, so if var2 is
- * -0xffff 8000 then -var2 is 0x0000 8000, not 0x0000 7fff.
- * This is the reason the L_shl function is used.
- *
- *
- * KEYWORDS:
- *
- *************************************************************************/
- Longword L_shift_r(Longword L_var1, Shortword var2)
- {
- Longword L_Out,
- L_rnd;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var2 < -31) {
- L_Out = 0;
- }
- else if (var2 < 0) {
- /* right shift */
- L_rnd = (Longword)(L_shl(L_var1, (Shortword)(var2 + 1)) & (Longword)0x1);
- L_Out = L_add(L_shl(L_var1, var2), L_rnd);
- }
- else
- L_Out = L_shl(L_var1, var2);
- // complexity = old_complexity + 3;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: norm_l
- *
- * PURPOSE:
- *
- * Get normalize shift count:
- *
- * A 32 bit number is input (possiblly unnormalized). Output
- * the positive (or zero) shift count required to normalize the
- * input.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0 <= swOut <= 31
- *
- *
- *
- * IMPLEMENTATION:
- *
- * Get normalize shift count:
- *
- * A 32 bit number is input (possiblly unnormalized). Output
- * the positive (or zero) shift count required to normalize the
- * input.
- *
- * If zero in input, return 0 as the shift count.
- *
- * For non-zero numbers, count the number of left shift
- * required to get the number to fall into the range:
- *
- * 0x4000 0000 >= normlzd number >= 0x7fff ffff (positive number)
- * or
- * 0x8000 0000 <= normlzd number < 0xc000 0000 (negative number)
- *
- * Return the number of shifts.
- *
- * This instruction corresponds exactly to the Full-Rate "norm"
- * instruction.
- *
- * KEYWORDS: norm, normalization
- *
- *************************************************************************/
- Shortword norm_l(Longword L_var1)
- {
- Shortword swShiftCnt;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (L_var1 != 0) {
- if (!(L_var1 & LW_SIGN)) {
- /* positive input */
- for (swShiftCnt = 0; !(L_var1 <= LW_MAX && L_var1 >= 0x40000000L);
- swShiftCnt++) {
- L_var1 = L_var1 << 1;
- }
- }
- else {
- /* negative input */
- for (swShiftCnt = 0;
- !(L_var1 >= LW_MIN && L_var1 < (Longword) 0xc0000000L);
- swShiftCnt++) {
- L_var1 = L_var1 << 1;
- }
- }
- }
- else {
- swShiftCnt = 0;
- }
- // complexity = old_complexity + 30;mark del
- return (swShiftCnt);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: norm_s
- *
- * PURPOSE:
- *
- * Get normalize shift count:
- *
- * A 16 bit number is input (possiblly unnormalized). Output
- * the positive (or zero) shift count required to normalize the
- * input.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0 <= swOut <= 15
- *
- *
- *
- * IMPLEMENTATION:
- *
- * Get normalize shift count:
- *
- * A 16 bit number is input (possiblly unnormalized). Output
- * the positive (or zero) shift count required to normalize the
- * input.
- *
- * If zero in input, return 0 as the shift count.
- *
- * For non-zero numbers, count the number of left shift
- * required to get the number to fall into the range:
- *
- * 0x4000 >= normlzd number >= 0x7fff (positive number)
- * or
- * 0x8000 <= normlzd number < 0xc000 (negative number)
- *
- * Return the number of shifts.
- *
- * This instruction corresponds exactly to the Full-Rate "norm"
- * instruction.
- *
- * KEYWORDS: norm, normalization
- *
- *************************************************************************/
- Shortword norm_s(Shortword var1)
- {
- short swShiftCnt;
- Longword L_var1;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_var1 = L_deposit_h(var1);
- swShiftCnt = norm_l(L_var1);
- // complexity = old_complexity + 15;mark del
- return (swShiftCnt);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_mult
- *
- * PURPOSE:
- *
- * Perform a fractional multipy of the two 16 bit input numbers
- * with saturation. Output a 32 bit number.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * IMPLEMENTATION:
- *
- * Multiply the two the two 16 bit input numbers. If the
- * result is within this range, left shift the result by one
- * and output the 32 bit number. The only possible overflow
- * occurs when var1==var2==-0x8000. In this case output
- * 0x7fff ffff.
- *
- * KEYWORDS: multiply, mult, mpy
- *
- *************************************************************************/
- Longword L_mult(Shortword var1, Shortword var2)
- {
- Longword L_product;
- // extern int complexity;mark del
- extern int saturation;
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var1 == SW_MIN && var2 == SW_MIN) {
- saturation = saturation + 1;
- L_product = LW_MAX; /* overflow */
- }
- else {
- L_product = (Longword) var1 *var2; /* integer multiply */
- L_product = L_product << 1;
- }
- // complexity = old_complexity + 1;mark del
- return (L_product);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: mult
- *
- * PURPOSE:
- *
- * Perform a fractional multipy of the two 16 bit input numbers
- * with saturation and truncation.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Perform a fractional multipy of the two 16 bit input
- * numbers. If var1 == var2 == -0x8000, output 0x7fff.
- * Otherwise output var1*var2 >> 15. The output is a
- * 16 bit number.
- *
- * KEYWORDS: mult, mulitply, mpy
- *
- *************************************************************************/
- Shortword mult(Shortword var1, Shortword var2)
- {
- Longword L_product;
- Shortword swOut;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_product = L_mult(var1, var2);
- swOut = extract_h(L_product);
- // complexity = old_complexity + 1;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: mult_r
- *
- * PURPOSE:
- *
- * Perform a fractional multipy and round of the two 16 bit
- * input numbers with saturation.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * This routine is defined as the concatenation of the multiply
- * operation and the round operation.
- *
- * The fractional multiply (L_mult) produces a saturated 32 bit
- * output. This is followed by a an add of 0x0000 8000 to the
- * 32 bit result. The result may overflow due to the add. If
- * so, the result is saturated. The 32 bit rounded number is
- * then shifted down 16 bits and returned as a Shortword.
- *
- *
- * KEYWORDS: multiply and round, round, mult_r, mpyr
- *
- *************************************************************************/
- Shortword mult_r(Shortword var1, Shortword var2)
- {
- Shortword swOut;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- swOut = round(L_mult(var1, var2));
- // complexity = old_complexity + 2;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_mac
- *
- * PURPOSE:
- *
- * Multiply accumulate. Fractionally multiply two 16 bit
- * numbers together with saturation. Add to that result to the
- * 32 bit input with saturation. Return the 32 bit result.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- * L_var3
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var2 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * IMPLEMENTATION:
- *
- * Fractionally multiply two 16 bit numbers together with
- * saturation. The only numbers which will cause saturation on
- * the multiply are 0x8000 * 0x8000.
- *
- * Add to that result to the 32 bit input with saturation.
- * Return the 32 bit result.
- *
- * Please note that this is not a true multiply accumulate as
- * most processors would implement it. The 0x8000*0x8000
- * causes and overflow for this instruction. On an most
- * processors this would cause an overflow only if the 32 bit
- * input added to it were positive or zero.
- *
- * KEYWORDS: mac, multiply accumulate
- *
- *************************************************************************/
- Longword L_mac(Longword L_var3, Shortword var1, Shortword var2)
- {
- Longword L_Out;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- L_Out = L_add(L_var3, L_mult(var1, var2));
- // complexity = old_complexity + 1;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME:mac_r
- *
- * PURPOSE:
- *
- * Multiply accumulate and round. Fractionally multiply two 16
- * bit numbers together with saturation. Add to that result to
- * the 32 bit input with saturation. Finally round the result
- * into a 16 bit number.
- *
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- * L_var3
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var2 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Fractionally multiply two 16 bit numbers together with
- * saturation. The only numbers which will cause saturation on
- * the multiply are 0x8000 * 0x8000.
- *
- * Add to that result to the 32 bit input with saturation.
- * Round the 32 bit result by adding 0x0000 8000 to the input.
- * The result may overflow due to the add. If so, the result
- * is saturated. The 32 bit rounded number is then shifted
- * down 16 bits and returned as a Shortword.
- *
- * Please note that this is not a true multiply accumulate as
- * most processors would implement it. The 0x8000*0x8000
- * causes and overflow for this instruction. On an most
- * processors this would cause an overflow only if the 32 bit
- * input added to it were positive or zero.
- *
- * KEYWORDS: mac, multiply accumulate, macr
- *
- *************************************************************************/
- Shortword mac_r(Longword L_var3, Shortword var1, Shortword var2)
- {
- Shortword swOut;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- swOut = round(L_add(L_var3,L_mult(var1, var2)));
- // complexity = old_complexity + 2; mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_msu
- *
- * PURPOSE:
- *
- * Multiply and subtract. Fractionally multiply two 16 bit
- * numbers together with saturation. Subtract from that result the
- * 32 bit input with saturation. Return the 32 bit result.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- * L_var3
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var2 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * IMPLEMENTATION:
- *
- * Fractionally multiply two 16 bit numbers together with
- * saturation. The only numbers which will cause saturation on
- * the multiply are 0x8000 * 0x8000.
- *
- * Subtract from that result to the 32 bit input with saturation.
- * Return the 32 bit result.
- *
- * Please note that this is not a true multiply accumulate as
- * most processors would implement it. The 0x8000*0x8000
- * causes and overflow for this instruction. On an most
- * processors this would cause an overflow only if the 32 bit
- * input added to it were negative or zero.
- *
- * KEYWORDS: mac, multiply accumulate, msu
- *
- *************************************************************************/
- Longword L_msu(Longword L_var3, Shortword var1, Shortword var2)
- {
- Longword L_Out;
- Longword L_mul;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- /* L_Out = L_sub(L_var3, L_mult(var1, var2)); */
- L_mul = _smpy(var1,var2);
- L_Out = _lssub(L_var3,L_mul);
- // complexity = old_complexity + 1;mark del
- return (L_Out);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: msu_r
- *
- * PURPOSE:
- *
- * Multiply subtract and round. Fractionally multiply two 16
- * bit numbers together with saturation. Subtract from that result
- * the 32 bit input with saturation. Finally round the result
- * into a 16 bit number.
- *
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- * var2
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var2 <= 0x0000 7fff.
- * L_var3
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var2 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0xffff 8000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Fractionally multiply two 16 bit numbers together with
- * saturation. The only numbers which will cause saturation on
- * the multiply are 0x8000 * 0x8000.
- *
- * Subtract from that result to the 32 bit input with saturation.
- * Round the 32 bit result by adding 0x0000 8000 to the input.
- * The result may overflow due to the add. If so, the result
- * is saturated. The 32 bit rounded number is then shifted
- * down 16 bits and returned as a Shortword.
- *
- * Please note that this is not a true multiply accumulate as
- * most processors would implement it. The 0x8000*0x8000
- * causes and overflow for this instruction. On an most
- * processors this would cause an overflow only if the 32 bit
- * input added to it were positive or zero.
- *
- * KEYWORDS: mac, multiply accumulate, macr
- *
- *************************************************************************/
- Shortword msu_r(Longword L_var3, Shortword var1, Shortword var2)
- {
- Shortword swOut;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- swOut = round(L_sub(L_var3, L_mult(var1, var2)));
- // complexity = old_complexity + 2;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: abs_s
- *
- * PURPOSE:
- *
- * Take the absolute value of the 16 bit input. An input of
- * -0x8000 results in a return value of 0x7fff.
- *
- * INPUTS:
- *
- * var1
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range 0xffff 8000 <= var1 <= 0x0000 7fff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * swOut
- * 16 bit short signed integer (Shortword) whose value
- * falls in the range
- * 0x0000 0000 <= swOut <= 0x0000 7fff.
- *
- * IMPLEMENTATION:
- *
- * Take the absolute value of the 16 bit input. An input of
- * -0x8000 results in a return value of 0x7fff.
- *
- * KEYWORDS: absolute value, abs
- *
- *************************************************************************/
- Shortword abs_s(Shortword var1)
- {
- Shortword swOut;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (var1 == SW_MIN) {
- swOut = SW_MAX;
- }
- else {
- if (var1 < 0)
- swOut = -var1;
- else
- swOut = var1;
- }
- // complexity = old_complexity + 1;mark del
- return (swOut);
- }
- /***************************************************************************
- *
- * FUNCTION NAME: L_abs
- *
- * PURPOSE:
- *
- * Take the absolute value of the 32 bit input. An input of
- * -0x8000 0000 results in a return value of 0x7fff ffff.
- *
- * INPUTS:
- *
- * L_var1
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- * OUTPUTS:
- *
- * none
- *
- * RETURN VALUE:
- *
- * L_Out
- * 32 bit long signed integer (Longword) whose value
- * falls in the range
- * 0x8000 0000 <= L_var1 <= 0x7fff ffff.
- *
- *
- *
- * KEYWORDS: absolute value, abs
- *
- *************************************************************************/
- Longword L_abs(Longword L_var1)
- {
- Longword L_Out;
- // extern int complexity;mark del
- // int old_complexity;mark del
- // old_complexity = complexity;mark del
- if (L_var1 == LW_MIN) {
- L_Out = LW_MAX;
- }
- else {
- if (L_var1 < 0)
- L_Out = -L_var1;
- else
- L_Out = L_var1;
- }
- // complexity = old_complexity + 3;mark del
- return (L_Out);
- }