mirror of https://github.com/hsoft/collapseos.git
131 lines
2.0 KiB
NASM
131 lines
2.0 KiB
NASM
; Glue code for the emulated environment
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.equ RAMSTART 0x4000
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.equ USER_CODE 0x4800
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.equ STDIO_PORT 0x00
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.equ STDIN_SEEK 0x01
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.equ FS_DATA_PORT 0x02
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.equ FS_SEEK_PORT 0x03
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.equ STDERR_PORT 0x04
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.inc "err.h"
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.inc "ascii.h"
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.inc "blkdev.h"
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.inc "fs.h"
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jp init ; 3 bytes
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; *** JUMP TABLE ***
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jp strncmp
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jp upcase
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jp findchar
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jp blkSel
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jp blkSet
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jp fsFindFN
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jp fsOpen
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jp fsGetB
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jp _blkGetB
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jp _blkPutB
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jp _blkSeek
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jp _blkTell
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jp printstr
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.inc "core.asm"
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.inc "str.asm"
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.equ BLOCKDEV_RAMSTART RAMSTART
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.equ BLOCKDEV_COUNT 3
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.inc "blockdev.asm"
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; List of devices
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.dw emulGetB, unsetZ
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.dw unsetZ, emulPutB
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.dw fsdevGetB, fsdevPutB
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.equ STDIO_RAMSTART BLOCKDEV_RAMEND
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.equ STDIO_GETC noop
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.equ STDIO_PUTC stderrPutC
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.inc "stdio.asm"
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.equ FS_RAMSTART STDIO_RAMEND
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.equ FS_HANDLE_COUNT 0
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.inc "fs.asm"
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init:
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di
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ld hl, 0xffff
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ld sp, hl
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ld a, 2 ; select fsdev
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ld de, BLOCKDEV_SEL
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call blkSel
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call fsOn
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; There's a special understanding between zasm.c and this unit: The
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; addresses 0xff00 and 0xff01 contain the two ascii chars to send to
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; zasm as the 3rd argument.
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ld a, (0xff00)
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ld (.zasmArgs+4), a
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ld a, (0xff01)
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ld (.zasmArgs+5), a
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ld hl, .zasmArgs
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call USER_CODE
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; signal the emulator we're done
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halt
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.zasmArgs:
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.db "0 1 XX", 0
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; *** I/O ***
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emulGetB:
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; the STDIN_SEEK port works by poking it twice. First poke is for high
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; byte, second poke is for low one.
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ld a, h
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out (STDIN_SEEK), a
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ld a, l
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out (STDIN_SEEK), a
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in a, (STDIO_PORT)
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or a ; cp 0
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jr z, .eof
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cp a ; ensure z
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ret
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.eof:
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jp unsetZ
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emulPutB:
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out (STDIO_PORT), a
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cp a ; ensure Z
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ret
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stderrPutC:
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out (STDERR_PORT), a
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cp a ; ensure Z
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ret
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fsdevGetB:
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ld a, e
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out (FS_SEEK_PORT), a
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ld a, h
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out (FS_SEEK_PORT), a
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ld a, l
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out (FS_SEEK_PORT), a
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in a, (FS_SEEK_PORT)
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or a
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ret nz
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in a, (FS_DATA_PORT)
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cp a ; ensure Z
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ret
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fsdevPutB:
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push af
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ld a, e
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out (FS_SEEK_PORT), a
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ld a, h
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out (FS_SEEK_PORT), a
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ld a, l
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out (FS_SEEK_PORT), a
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in a, (FS_SEEK_PORT)
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or a
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jr nz, .error
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pop af
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out (FS_DATA_PORT), a
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cp a ; ensure Z
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ret
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.error:
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pop af
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jp unsetZ ; returns
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