collapseos/tools/emul/zasm_glue.asm

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; Glue code for the emulated environment
.equ RAMSTART 0x4000
.equ USER_CODE 0x4800
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.equ STDIO_PORT 0x00
.equ STDIN_SEEK 0x01
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.equ FS_DATA_PORT 0x02
.equ FS_SEEK_PORT 0x03
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jp init ; 3 bytes
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; *** JUMP TABLE ***
jp strncmp
jp addDE
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jp addHL
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jp upcase
jp unsetZ
jp intoDE
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jp intoHL
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jp findchar
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jp parseHexPair
jp blkSel
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#include "core.asm"
.equ BLOCKDEV_RAMSTART RAMSTART
.equ BLOCKDEV_COUNT 3
#include "blockdev.asm"
; List of devices
.dw emulGetC, 0, emulSeek, emulTell
.dw 0, emulPutC, 0, 0
.dw fsdevGetC, fsdevPutC, fsdevSeek, fsdevTell
.equ FS_RAMSTART BLOCKDEV_RAMEND
.equ FS_HANDLE_COUNT 0
#include "fs.asm"
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init:
di
; We put the stack at the end of the kernel memory
ld hl, USER_CODE-1
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ld sp, hl
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ld a, 2 ; select fsdev
ld de, BLOCKDEV_GETC
call blkSel
call fsOn
ld h, 0 ; input blkdev
ld l, 1 ; output blkdev
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call USER_CODE
; signal the emulator we're done
halt
emulGetC:
in a, (STDIO_PORT)
or a ; cp 0
jr z, .eof
cp a ; ensure z
ret
.eof:
call unsetZ
ret
emulPutC:
out (STDIO_PORT), a
ret
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emulSeek:
; the STDIN_SEEK port works by poking it twice. First poke is for high
; byte, second poke is for low one.
ld a, h
out (STDIN_SEEK), a
ld a, l
out (STDIN_SEEK), a
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ret
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emulTell:
; same principle as STDIN_SEEK
in a, (STDIN_SEEK)
ld h, a
in a, (STDIN_SEEK)
ld l, a
ret
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fsdevGetC:
in a, (FS_DATA_PORT)
cp a ; ensure Z
ret
fsdevPutC:
out (FS_DATA_PORT), a
ret
fsdevSeek:
push af
ld a, l
out (FS_SEEK_PORT), a
ld a, h
out (FS_SEEK_PORT), a
pop af
ret
fsdevTell:
push af
in a, (FS_SEEK_PORT)
ld l, a
in a, (FS_SEEK_PORT)
ld h, a
pop af
ret