cc65/libsrc/telestrat/write.s

;
; jede jede@oric.org 2017-01-22

        .export         _write
        .import         popax, popptr1
        .importzp       ptr1, ptr2, ptr3, tmp1

        .include        "telestrat.inc"

; int write (int fd, const void* buf, int count);
.proc   _write

        sta     ptr3
        stx     ptr3+1          ; save count as result

        eor     #$FF
        sta     ptr2
        txa
        eor     #$FF
        sta     ptr2+1          ; remember -count-1

        jsr     popptr1         ; get buf
        jsr     popax           ; get fd and discard

        ; if fd=0001 then it stdout
        cpx 	#0
        beq 	next
        jmp 	L1
next:		
        cmp 	#1
        beq 	L1		
		
        ; here it's a file opened
        lda 	ptr1
        sta  	PTR_READ_DEST
        lda 	ptr1+1
        sta  	PTR_READ_DEST+1
        lda 	ptr3
        ldy 	ptr3+1
        BRK_TELEMON  XFWRITE
        ;  compute nb of bytes written
       

        lda     PTR_READ_DEST+1
        sec
        sbc     ptr1+1
        tax			
        lda     PTR_READ_DEST
        sec
        sbc     ptr1
        rts
		
		
L1:     inc     ptr2
        bne     L2
        inc     ptr2+1
        beq     L9
L2:     ldy     #0
        lda     (ptr1),y
        tax
        cpx     #$0A            ; check for \n
        bne     L3
        BRK_TELEMON  XWR0       ; macro send char to screen (channel 0 in telemon terms)
        lda     #$0D            ; return to the beggining of the line
        BRK_TELEMON  XWR0       ; macro
	

        ldx     #$0D
L3:     
        BRK_TELEMON  XWR0       ; macro

        inc     ptr1
        bne     L1
        inc     ptr1+1
        jmp     L1

        ; No error, return count

L9:     lda     ptr3
        ldx     ptr3+1
        rts

.endproc