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- ; 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
- .inc "err.h"
- .inc "ascii.h"
- .inc "blkdev.h"
- .inc "fs.h"
-
- jp init ; 3 bytes
- ; *** JUMP TABLE ***
- jp strncmp
- jp upcase
- jp findchar
- jp blkSel
- jp blkSet
- jp fsFindFN
- jp fsOpen
- jp fsGetB
- jp _blkGetB
- jp _blkPutB
- jp _blkSeek
- jp _blkTell
- jp printstr
-
- .inc "core.asm"
- .inc "str.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
- ; There's a special understanding between zasm.c and this unit: The
- ; addresses 0xff00 and 0xff01 contain the two ascii chars to send to
- ; zasm as the 3rd argument.
- ld a, (0xff00)
- ld (.zasmArgs+4), a
- ld a, (0xff01)
- ld (.zasmArgs+5), a
- ld hl, .zasmArgs
- call USER_CODE
- ; signal the emulator we're done
- halt
-
- .zasmArgs:
- .db "0 1 XX", 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
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