_csl_begincriticalsection.asm

来自「TI达芬奇dm644x各硬件模块测试代码」· 汇编 代码 · 共 56 行

****************************************************************************
*                    E X P O R T E D     F U N C T I O N S
****************************************************************************
    .global __CSL_beginCriticalSection

****************************************************************************
*                         P A S S - T H R U   C O D E
****************************************************************************

  .text
  .state32

; the FIQIRQ bit   [6:7]   in PSR
__ARM_CPSR_FIQIRQ_MASK   .equ   0x000000C0
__ARM_CPSR_FIQIRQ_SHIFT  .equ   0x06


****************************************************************************
*                       P U B L I C   F U N C T I O N S
****************************************************************************

****************************************************************************
*   CSL_CriticalSectionState
*       _CSL_beginCriticalSection (
*           void
*   )
****************************************************************************

__CSL_beginCriticalSection:
    ; return value in R0 -> the FIQIRQ bit pattern

    mrs r0, cpsr
    orr r1, r0, #__ARM_CPSR_FIQIRQ_MASK ; set the FIQIRQ-bits to disable
    msr cpsr, r1

    ; make return value
    and r0, r0, #__ARM_CPSR_FIQIRQ_MASK      ; mask out irrelevant bits
    mov r0, r0, lsr #__ARM_CPSR_FIQIRQ_SHIFT ; shift into LSBs

    bx   lr

    .state16

    .global $_CSL_beginCriticalSection

$_CSL_beginCriticalSection:
    bx  pc
    nop
    .state32
    b   __CSL_beginCriticalSection

****************************************************************************
* End of _CSL_beginCriticalSection.asm
****************************************************************************