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cc65/libsrc/cbm/write.s
cuz cd552515fb Move more common code into rwcommon.s.
Move declaration of __errno into errno.inc.


git-svn-id: svn://svn.cc65.org/cc65/trunk@1552 b7a2c559-68d2-44c3-8de9-860c34a00d81
2002-11-20 18:14:35 +00:00

116 lines
2.5 KiB
ArmAsm

;
; Ullrich von Bassewitz, 16.11.2002
;
; int write (int fd, const void* buf, unsigned count);
;
.export _write
.constructor initstdout
.import SETLFS, OPEN, CKOUT, BSOUT, CLRCH
.import rwcommon
.import __oserror
.importzp sp, ptr1, ptr2, ptr3
.include "fcntl.inc"
.include "cbm.inc"
.include "filedes.inc"
;--------------------------------------------------------------------------
; initstdout: Open the stdout and stderr file descriptors for the screen.
.proc initstdout
lda #LFN_WRITE
sta fdtab+STDOUT_FILENO
sta fdtab+STDERR_FILENO
lda #CBMDEV_SCREEN
sta unittab+STDOUT_FILENO
sta unittab+STDERR_FILENO
lda #STDOUT_FILENO + LFN_OFFS
jsr @L1
lda #STDERR_FILENO + LFN_OFFS
@L1: ldx #CBMDEV_SCREEN
ldy #$FF
jsr SETLFS
jmp OPEN ; Will always succeed
.endproc
;--------------------------------------------------------------------------
; _write
.proc _write
jsr rwcommon ; Pop params, check handle
bcs errout ; Invalid handle, errno already set
; Check if the LFN is valid and the file is open for writing
adc #LFN_OFFS ; Carry is already clear
tax
lda fdtab-LFN_OFFS,x; Get flags for this handle
and #LFN_WRITE ; File open for writing?
beq notopen
; Valid lfn. Make it the output file
jsr CKOUT
bcs error
bcc @L2
; Output the next character from the buffer
@L0: ldy #0
lda (ptr2),y
inc ptr2
bne @L1
inc ptr2+1 ; A = *buf++;
@L1: jsr BSOUT
bcs error ; Bail out on errors
; Count characters written
inc ptr3
bne @L2
inc ptr3+1
; Decrement count
@L2: inc ptr1
bne @L0
inc ptr1+1
bne @L0
; Wrote all chars, close the output channel
jsr CLRCH
; Return the number of chars written
lda ptr3
ldx ptr3+1
rts
; Error entry, file is not open
notopen:
lda #3 ; File not open
bne error
; Error entry, status not ok
error5: lda #5 ; Device not present
error: sta __oserror
errout: lda #$FF
tax ; Return -1
rts
.endproc