cpu_a.asm
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上传日期：2017-01-28
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- ;********************************************************************************************************
- ; uC/CPU
- ; CPU CONFIGURATION & PORT LAYER
- ;
- ; (c) Copyright 2004-2008; Micrium, Inc.; Weston, FL
- ;
- ; All rights reserved. Protected by international copyright laws.
- ;
- ; uC/CPU is provided in source form for FREE evaluation, for educational
- ; use or peaceful research. If you plan on using uC/CPU in a commercial
- ; product you need to contact Micrium to properly license its use in your
- ; product. We provide ALL the source code for your convenience and to
- ; help you experience uC/CPU. The fact that the source code is provided
- ; does NOT mean that you can use it without paying a licensing fee.
- ;
- ; Knowledge of the source code may NOT be used to develop a similar product.
- ;
- ; Please help us continue to provide the Embedded community with the finest
- ; software available. Your honesty is greatly appreciated.
- ;********************************************************************************************************
- ;********************************************************************************************************
- ;
- ; CPU PORT FILE
- ;
- ; ARM-Cortex-M3
- ; RealView Development Suite
- ; RealView Microcontroller Development Kit (MDK)
- ; ARM Developer Suite (ADS)
- ; Keil uVision
- ;
- ; Filename : cpu_a.asm
- ; Version : V1.19
- ; Programmer(s) : BAN
- ;********************************************************************************************************
- ;********************************************************************************************************
- ; PUBLIC FUNCTIONS
- ;********************************************************************************************************
- EXPORT CPU_IntDis
- EXPORT CPU_IntEn
- EXPORT CPU_SR_Save
- EXPORT CPU_SR_Restore
-
- EXPORT CPU_CntLeadZeros
- EXPORT CPU_RevBits
- EXPORT CPU_WaitForInt
- EXPORT CPU_WaitForExcept
- ;********************************************************************************************************
- ; CODE GENERATION DIRECTIVES
- ;********************************************************************************************************
- AREA |.text|, CODE, READONLY, ALIGN=2
- THUMB
- REQUIRE8
- PRESERVE8
- ;$PAGE
- ;*********************************************************************************************************
- ; DISABLE and ENABLE INTERRUPTS
- ;
- ; Description : Disable/Enable interrupts.
- ;
- ; Prototypes : void CPU_IntDis(void);
- ; void CPU_IntEn (void);
- ;*********************************************************************************************************
- CPU_IntDis
- CPSID I
- BX LR
- CPU_IntEn
- CPSIE I
- BX LR
- ;*********************************************************************************************************
- ; CRITICAL SECTION FUNCTIONS
- ;
- ; Description : Disable/Enable interrupts by preserving the state of interrupts. Generally speaking, the
- ; state of the interrupt disable flag is stored in the local variable 'cpu_sr' & interrupts
- ; are then disabled ('cpu_sr' is allocated in all functions that need to disable interrupts).
- ; The previous interrupt state is restored by copying 'cpu_sr' into the CPU's status register.
- ;
- ; Prototypes : CPU_SR CPU_SR_Save (void);
- ; void CPU_SR_Restore(CPU_SR cpu_sr);
- ;
- ;
- ; Note(s) : (1) These functions are used in general like this:
- ;
- ; void Task (void *p_arg)
- ; {
- ; /* Allocate storage for CPU status register */
- ; #if (CPU_CFG_CRITICAL_METHOD == CPU_CRITICAL_METHOD_STATUS_LOCAL)
- ; CPU_SR cpu_sr;
- ; #endif
- ;
- ; :
- ; :
- ; CPU_CRITICAL_ENTER(); /* cpu_sr = CPU_SR_Save(); */
- ; :
- ; :
- ; CPU_CRITICAL_EXIT(); /* CPU_SR_Restore(cpu_sr); */
- ; :
- ; :
- ; }
- ;*********************************************************************************************************
- CPU_SR_Save
- MRS R0, PRIMASK ; Set prio int mask to mask all (except faults)
- CPSID I
- BX LR
- CPU_SR_Restore ; See Note #2.
- MSR PRIMASK, R0
- BX LR
- ;$PAGE
- ;********************************************************************************************************
- ; COUNT LEADING ZEROS
- ;
- ; Description : Counts the number of binary zero bits before the first binary one bit in the argument.
- ; If the argument is zero, the value 32 is returned.
- ;
- ; Prototypes : CPU_INT32U CPU_CntLeadZeros (CPU_INT32U val)
- ;
- ; Argument(s) : val variable to count leading zeros
- ;********************************************************************************************************
- CPU_CntLeadZeros
- CLZ R0, R0 ; Count leading zeros
- BX LR
- ;********************************************************************************************************
- ; REVERSE BITS
- ;
- ; Description : Reverses the bits in the argument.
- ;
- ; Prototypes : CPU_INT32U CPU_RevBits (CPU_INT32U val)
- ;
- ; Argument(s) : val variable to reverse
- ;********************************************************************************************************
- CPU_RevBits
- RBIT R0, R0 ; Reverse bits
- BX LR
- ;$PAGE
- ;********************************************************************************************************
- ; WAIT FOR INTERRUPT
- ;
- ; Description : Enters sleep state, which will be exited when an interrupt is received.
- ;
- ; Prototypes : void CPU_WaitForInt (void)
- ;
- ; Argument(s) : none.
- ;********************************************************************************************************
- CPU_WaitForInt
- WFI ; Wait for interrupt
- BX LR
- ;********************************************************************************************************
- ; WAIT FOR EXCEPTION
- ;
- ; Description : Enters sleep state, which will be exited when an exception is received.
- ;
- ; Prototypes : void CPU_WaitForExcept (void)
- ;
- ; Argument(s) : none.
- ;********************************************************************************************************
- CPU_WaitForExcept
- WFE ; Wait for exception
- BX LR
- ;$PAGE
- ;********************************************************************************************************
- ; CPU ASSEMBLY PORT FILE END
- ;********************************************************************************************************
- END
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