memcmp.a51

cy68013a USB2.0 highspeed mass storage source code

NAME	MEMCMP

public _mymemcmpa
public sendprev
EXTRN idata (prevCmd)

$include (fx2regs.inc)

MEMCMPSEG     SEGMENT CODE 

	RSEG  MEMCMPSEG
	USING	0

; unsigned char mymemcmpa(unsigned char idata * s1, unsigned char xdata * s2, unsigned char len)
; s1 in R7
; s2 in R4,R5
; len in R3

_mymemcmpa:
        MOV     DPL,R5
        MOV     DPH,R4
        MOV     R1,AR7
loop:
        MOVX    A,@DPTR
        MOV     B,A
        MOV     A,@R1
        CJNE    A,B,fail
        INC     DPTR
        INC     R1
        DJNZ    R3,loop

	MOV  	R7,#00H
        RET

fail:
        MOV     R7,#01H
        RET

; Send prevCmd out using GPIF.
; R0 = ptr
; R7 = loop ctr
; R6 = cmd_lsb
sendprev:
       MOV     R7, #06H
       MOV     R0, #prevCmd

cmd_loop:
       MOV     A,@R0
       MOV     R6, A            ; cmd_lsb = *ptr++
       INC     R0

;      // make sure GPIF is not busy
gpif_loop:
       MOV     A,GPIFTRIG
       JNB     ACC.7,gpif_loop

      ; trigger the GPIF          XGPIFSGLDATH = *ptr++;
       MOV     A,@R0
       INC     R0
       MOV     DPTR,#XGPIFSGLDATH  ;#0E6F0H               
       MOVX    @dptr, a
       MOV     a, R6
       INC     dptr
       MOVX    @dptr, a           ;XGPIFSGLDATLX = cmd_lsb
       djnz    R7, cmd_loop
       RET

	END