wordcheck.s

来自「这是操作系统中的内存管理的全部debug程序」· S 代码 · 共 35 行

******************************************************************************
* WordCheck.S   $Revision:   1.1  $                      Liteon Confidential
*
*
* Description:
*
* This file insures a pointer is on a long word boundary.
*
* No. Date     Who Function          Description ofChange
* --- -------- --- ----------------- ------------------------------------------
* --- -------- --- ----------------- ------------------------------------------
* 001 3/25/05  ***                   Create   
******************************************************************************/

   EXPORT WordPointerCheck

   AREA    WordCheck, CODE, READONLY
******************************************************************************
* WordPointercheck 
*
* Description:
* This module insures a pointer is on a long word boundary.
*
******************************************************************************/
   
WordPointerCheck

   STMFD SP!, {LR}    ; store link register on stack
   TST   R0, #3       ; test two lowest bits to see if on longword boundary
   
   BICNE R0, R0, #3   ; if not on boundary, clear two lowest bits        

   LDMFD SP!, {PC}    ; return
   
   END