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;
; Ullrich von Bassewitz, 22.11.2002
;
; size_t __fastcall__ fwrite (const void* buf, size_t size, size_t count, FILE* file);
; /* Write to a file */
;
.export _fwrite
.import _write
.import pushax, incsp6, addysp, ldaxysp, pushwysp, return0
.import tosumulax, tosudivax
.importzp ptr1
.include "errno.inc"
.include "_file.inc"
; ------------------------------------------------------------------------
; Code
.proc _fwrite
; Save file and place it into ptr1
sta file
sta ptr1
stx file+1
stx ptr1+1
; Check if the file is open
ldy #_FILE::f_flags
lda (ptr1),y
and #_FOPEN ; Is the file open?
bne @L2 ; Branch if yes
; File not open
@L1: lda #EBADF
jsr __seterrno ; Returns with A = 0
tax ; A = X = 0
jmp incsp6
; Check if the stream is in an error state
@L2: lda (ptr1),y ; get file->f_flags again
and #_FERROR
bne @L1
; Build the stackframe for write()
ldy #_FILE::f_fd
lda (ptr1),y
ldx #$00
jsr pushax ; file->f_fd
ldy #9
jsr pushwysp ; buf
; Stack is now: buf/size/count/file->fd/buf
; Calculate the number of bytes to write: count * size
ldy #7
jsr pushwysp ; count
ldy #9
jsr ldaxysp ; Get size
jsr tosumulax ; count * size -> a/x
; Check if the number of bytes is zero. Don't call write in this case
cpx #0
bne @L3
cmp #0
bne @L3
; The number of bytes to write is zero, just return count
ldy #5
jsr ldaxysp ; Get count
ldy #10
jmp addysp ; Drop params, return
; Call write(). This will leave the original 3 params on the stack
@L3: jsr _write
; Check for errors in write
cpx #$FF
bne @L4
cmp #$FF
bne @L4
; Error in write. Set the stream error flag and bail out. errno is already
; set by write().
lda file
sta ptr1
lda file+1
sta ptr1+1
ldy #_FILE::f_flags
lda (ptr1),y
ora #_FERROR
sta (ptr1),y
bne @L1 ; Return zero
; Write was ok. Return the number of items successfully written. Since we've
; checked for bytes == 0 above, size cannot be zero here, so the division is
; safe.
@L4: jsr pushax ; Push number of bytes written
ldy #5
jsr ldaxysp ; Get size
jsr tosudivax ; bytes / size -> a/x
jmp incsp6 ; Drop params, return
.endproc
; ------------------------------------------------------------------------
; Data
.bss
file: .res 2
|
