collapseos/apps/zasm/io.asm

; *** Variables ***
.equ	IO_IN_GETC	IO_RAMSTART
.equ	IO_IN_PUTC	IO_IN_GETC+2
.equ	IO_IN_SEEK	IO_IN_PUTC+2
.equ	IO_IN_TELL	IO_IN_SEEK+2
.equ	IO_OUT_GETC	IO_IN_TELL+2
.equ	IO_OUT_PUTC	IO_OUT_GETC+2
.equ	IO_OUT_SEEK	IO_OUT_PUTC+2
.equ	IO_OUT_TELL	IO_OUT_SEEK+2
; see ioPutBack below
.equ	IO_PUTBACK_BUF	IO_OUT_TELL+2
.equ	IO_RAMEND	IO_PUTBACK_BUF+1

; *** Code ***

ioInit:
	xor	a
	ld	(IO_PUTBACK_BUF), a
	ret

ioGetC:
	ld	a, (IO_PUTBACK_BUF)
	or	a		; cp 0
	jr	nz, .getback
	ld	ix, (IO_IN_GETC)
	jp	(ix)
.getback:
	push	af
	xor	a
	ld	(IO_PUTBACK_BUF), a
	pop	af
	ret

; Put back non-zero character A into the "ioGetC stack". The next ioGetC call,
; instead of reading from IO_IN_GETC, will return that character. That's the
; easiest way I found to handle the readWord/gotoNextLine problem.
ioPutBack:
	ld	(IO_PUTBACK_BUF), a
	ret

ioPutC:
	ld	ix, (IO_OUT_PUTC)
	jp	(ix)

ioSeek:
	ld	ix, (IO_IN_SEEK)
	jp	(ix)

ioTell:
	ld	ix, (IO_IN_TELL)
	jp	(ix)
zasm: Read from and write to streams instead of memory 2019-05-10 05:36:03 +10:00			`; * Variables *`
zasm: use blkdev IDs as input and output This will soon allow use to seek and tell on input, which is necessary for a second pass which is necessary for forward symbol references. This require making `blkSel` a bit more flexible. Rather than having one global selected blkdev, each app can select its own, in its own memory space. 2019-05-11 08:20:43 +10:00			`.equ IO_IN_GETC IO_RAMSTART`
			`.equ IO_IN_PUTC IO_IN_GETC+2`
			`.equ IO_IN_SEEK IO_IN_PUTC+2`
			`.equ IO_IN_TELL IO_IN_SEEK+2`
			`.equ IO_OUT_GETC IO_IN_TELL+2`
			`.equ IO_OUT_PUTC IO_OUT_GETC+2`
			`.equ IO_OUT_SEEK IO_OUT_PUTC+2`
			`.equ IO_OUT_TELL IO_OUT_SEEK+2`
zasm: big I/O overhaul Instead of buffering input in memory one line at a time, we go in "just in time" mode and always read contents directly from I/O, without buffering. It forces us to implement a `ioPutback` scheme, but on the other hand it greatly simplifies cases where multiple tokens are on the same line (when a label is directly followed by an instruction). The end result feels much more solid and less hackish. 2019-05-16 21:53:42 +10:00			`; see ioPutBack below`
			`.equ IO_PUTBACK_BUF IO_OUT_TELL+2`
			`.equ IO_RAMEND IO_PUTBACK_BUF+1`
zasm: Read from and write to streams instead of memory 2019-05-10 05:36:03 +10:00
			`; * Code *`

zasm: big I/O overhaul Instead of buffering input in memory one line at a time, we go in "just in time" mode and always read contents directly from I/O, without buffering. It forces us to implement a `ioPutback` scheme, but on the other hand it greatly simplifies cases where multiple tokens are on the same line (when a label is directly followed by an instruction). The end result feels much more solid and less hackish. 2019-05-16 21:53:42 +10:00			`ioInit:`
			`xor a`
			`ld (IO_PUTBACK_BUF), a`
			`ret`

zasm: Read from and write to streams instead of memory 2019-05-10 05:36:03 +10:00			`ioGetC:`
zasm: big I/O overhaul Instead of buffering input in memory one line at a time, we go in "just in time" mode and always read contents directly from I/O, without buffering. It forces us to implement a `ioPutback` scheme, but on the other hand it greatly simplifies cases where multiple tokens are on the same line (when a label is directly followed by an instruction). The end result feels much more solid and less hackish. 2019-05-16 21:53:42 +10:00			`ld a, (IO_PUTBACK_BUF)`
			`or a ; cp 0`
			`jr nz, .getback`
zasm: use blkdev IDs as input and output This will soon allow use to seek and tell on input, which is necessary for a second pass which is necessary for forward symbol references. This require making `blkSel` a bit more flexible. Rather than having one global selected blkdev, each app can select its own, in its own memory space. 2019-05-11 08:20:43 +10:00			`ld ix, (IO_IN_GETC)`
zasm: Read from and write to streams instead of memory 2019-05-10 05:36:03 +10:00			`jp (ix)`
zasm: big I/O overhaul Instead of buffering input in memory one line at a time, we go in "just in time" mode and always read contents directly from I/O, without buffering. It forces us to implement a `ioPutback` scheme, but on the other hand it greatly simplifies cases where multiple tokens are on the same line (when a label is directly followed by an instruction). The end result feels much more solid and less hackish. 2019-05-16 21:53:42 +10:00			`.getback:`
			`push af`
			`xor a`
			`ld (IO_PUTBACK_BUF), a`
			`pop af`
			`ret`

			`; Put back non-zero character A into the "ioGetC stack". The next ioGetC call,`
			`; instead of reading from IO_IN_GETC, will return that character. That's the`
			`; easiest way I found to handle the readWord/gotoNextLine problem.`
			`ioPutBack:`
			`ld (IO_PUTBACK_BUF), a`
			`ret`
zasm: Read from and write to streams instead of memory 2019-05-10 05:36:03 +10:00
			`ioPutC:`
zasm: use blkdev IDs as input and output This will soon allow use to seek and tell on input, which is necessary for a second pass which is necessary for forward symbol references. This require making `blkSel` a bit more flexible. Rather than having one global selected blkdev, each app can select its own, in its own memory space. 2019-05-11 08:20:43 +10:00			`ld ix, (IO_OUT_PUTC)`
zasm: Read from and write to streams instead of memory 2019-05-10 05:36:03 +10:00			`jp (ix)`

zasm: change ioRewind to ioSeek Will need it soon. 2019-05-16 03:41:56 +10:00			`ioSeek:`
zasm: read input in two passes 2019-05-11 10:32:05 +10:00			`ld ix, (IO_IN_SEEK)`
			`jp (ix)`

zasm: big local symbols overhaul 2019-05-16 10:07:21 +10:00			`ioTell:`
			`ld ix, (IO_IN_TELL)`
			`jp (ix)`