strwrite.asm

TMS320F2407A的例程

********************************************************************************
* Function: PFUNC_strWrite()                                                   *
* File: strread.asm                                                            *
* Author: David M. Alter, Texas Instruments Inc.                               *
* DSP: TMS320C24x                                                              *
* Language: TMS320C24x assembly (C-callable)                                   *
* Description: Copies a string from data space to program space.               *
* Function Prototype:                                                          *
*   extern void PFUNC_strWrite(char *, char *);                                *
* Useage: PFUNC_strWrite(addrProg, strData);                                   *
* Passed Parameters:                                                           *
*   char *addrProg = address of program space string                           *
*   char *strData = pointer to data space string                               *
* Return Value: none                                                           *
* Notes: none                                                                  *
* History:                                                                     *
*   04/04/02 - original (D. Alter)                                             *
********************************************************************************

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**************************************************************

        .def _PFUNC_strWrite

        .asg	AR1, SP

        .text
_PFUNC_strWrite:
        POPD    *+                          ;pop return address off HW stack and push onto SW stack
        SAR     SP, *                       ;save SP to stack
        LAR     AR2, *, AR2                 ;make a copy of the stack pointer in AR2
        SBRK    #2                          ;AR2 now points to 1st passed parameter
        LACC    *-                          ;load 1st passed parameter into ACC
        LAR     AR2, *                      ;load 2nd passed parameter into AR2

_PFUNC_strWrite1:
        TBLW    *                           ;write character to program space
        ADD     #1                          ;increment ACC (program space pointer)
        LAR     AR3, *+, AR3                ;AR3 = current character
        BANZ    _PFUNC_strWrite1, *, AR2    ;branch if character not null
 
        MAR     *, SP                       ;ARP=SP
        MAR     *-                          ;decrement SP
        PSHD    *                           ;push return address back onto the HW stack
        RET                                 ;return

        .end