collapseos/tools/emul/zasm/glue.asm
Virgil Dupras 7cf3ed38da Extract str.asm from core.asm and make core included by userspace
Most of register fiddling routines (which is now the only thing contained
in care.asm) are used by almost all userspace apps, often in inner loops.

That makes the penalty of using jump tables for those a bit too high.
Moreover, it burdens jump tables needlessly.

Because this unit is very small (now that string routines are out), it makes
sense to always include it in binaries.
2019-11-14 10:14:15 -05:00

126 lines
1.8 KiB
NASM

; Glue code for the emulated environment
.equ RAMSTART 0x4000
.equ USER_CODE 0x4800
.equ STDIO_PORT 0x00
.equ STDIN_SEEK 0x01
.equ FS_DATA_PORT 0x02
.equ FS_SEEK_PORT 0x03
.equ STDERR_PORT 0x04
jp init ; 3 bytes
; *** JUMP TABLE ***
jp strncmp
jp upcase
jp findchar
jp parseHex
jp parseHexPair
jp blkSel
jp blkSet
jp fsFindFN
jp fsOpen
jp fsGetB
jp parseArgs
jp _blkGetB
jp _blkPutB
jp _blkSeek
jp _blkTell
jp printstr
.inc "core.asm"
.inc "str.asm"
.inc "err.h"
.inc "ascii.h"
.inc "parse.asm"
.equ BLOCKDEV_RAMSTART RAMSTART
.equ BLOCKDEV_COUNT 3
.inc "blockdev.asm"
; List of devices
.dw emulGetB, unsetZ
.dw unsetZ, emulPutB
.dw fsdevGetB, fsdevPutB
.equ STDIO_RAMSTART BLOCKDEV_RAMEND
.equ STDIO_GETC noop
.equ STDIO_PUTC stderrPutC
.inc "stdio.asm"
.equ FS_RAMSTART STDIO_RAMEND
.equ FS_HANDLE_COUNT 0
.inc "fs.asm"
init:
di
ld hl, 0xffff
ld sp, hl
ld a, 2 ; select fsdev
ld de, BLOCKDEV_SEL
call blkSel
call fsOn
ld hl, .zasmArgs
call USER_CODE
; signal the emulator we're done
halt
.zasmArgs:
.db "0 1", 0
; *** I/O ***
emulGetB:
; 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
in a, (STDIO_PORT)
or a ; cp 0
jr z, .eof
cp a ; ensure z
ret
.eof:
jp unsetZ
emulPutB:
out (STDIO_PORT), a
cp a ; ensure Z
ret
stderrPutC:
out (STDERR_PORT), a
cp a ; ensure Z
ret
fsdevGetB:
ld a, e
out (FS_SEEK_PORT), a
ld a, h
out (FS_SEEK_PORT), a
ld a, l
out (FS_SEEK_PORT), a
in a, (FS_SEEK_PORT)
or a
ret nz
in a, (FS_DATA_PORT)
cp a ; ensure Z
ret
fsdevPutB:
push af
ld a, e
out (FS_SEEK_PORT), a
ld a, h
out (FS_SEEK_PORT), a
ld a, l
out (FS_SEEK_PORT), a
in a, (FS_SEEK_PORT)
or a
jr nz, .error
pop af
out (FS_DATA_PORT), a
cp a ; ensure Z
ret
.error:
pop af
jp unsetZ ; returns