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cc65/libsrc/atmos/read.s
Oliver Schmidt 1d1ba3ed3b Adjusted constructors.
The constructors are _NOT_ allowed anymore to access the BSS. Rather they must use the DATA segment or the INIT segment. The latter isn't cleared at any point so the constructors may use it to expose values to the main program. However they must make sure to always write the values as they are not pre-initialized.
2016-03-16 16:28:32 +01:00

86 lines
1.9 KiB
ArmAsm

;
; 2014-08-22, Greg King
;
; int read (int fd, void* buf, unsigned count);
;
; This function is a hack! It lets us get text from the stdin console.
;
.export _read
.constructor initstdin
.import popax
.importzp ptr1, ptr2, ptr3
.forceimport disable_caps
.macpack generic
.include "atmos.inc"
.proc _read
sta ptr3
stx ptr3+1 ; save count as result
eor #$FF
sta ptr2
txa
eor #$FF
sta ptr2+1 ; Remember -count-1
jsr popax ; get buf
sta ptr1
stx ptr1+1
jsr popax ; get fd and discard
L1: inc ptr2
bnz L2
inc ptr2+1
bze L9 ; no more room in buf
; If there are no more characters in BASIC's input buffer, then get a line from
; the console into that buffer.
L2: ldx text_count
bpl L3
jsr GETLINE
ldx #<(0 - 1)
L3: inx
lda BASIC_BUF,x
bnz L4 ; (zero-terminated buffer)
ldx #<-1
lda #$0A ; return newline char. at end of line
L4: stx text_count
ldy #0
sta (ptr1),y
inc ptr1
bnz L1
inc ptr1+1
bnz L1 ; branch always
; No error, return count.
L9: lda ptr3
ldx ptr3+1
rts
.endproc
;--------------------------------------------------------------------------
; initstdin: Reset the stdin console.
.segment "ONCE"
initstdin:
ldx #<-1
stx text_count
rts
;--------------------------------------------------------------------------
.segment "INIT"
text_count:
.res 1