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collapseos/apps/zasm/io.asm

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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)