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https://github.com/hsoft/collapseos.git
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73c3fc7947
Move load/save to blkdev_cmds and add a new "poke" builtin shell cmd that is the mirror of "peek" and strictly uses stdio (no blkdev involved). This allows us to slim the minimal OS size but, more importantly, change the behavior of "load" so that we don't expect GetC to block until Z is set. This way, using "load X" with X being larger than the blkdev size won't block forever. This also brings our RC2014 minimal kernel below the 1K mark again.
91 lines
1.3 KiB
NASM
91 lines
1.3 KiB
NASM
; stdio
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;
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; Allows other modules to print to "standard out", and get data from "stamdard
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; in", that is, the console through which the user is connected in a decoupled
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; manner.
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;
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; *** VARIABLES ***
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; Used to store formatted hex values just before printing it.
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.equ STDIO_HEX_FMT STDIO_RAMSTART
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.equ STDIO_GETC STDIO_HEX_FMT+2
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.equ STDIO_PUTC STDIO_GETC+2
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.equ STDIO_RAMEND STDIO_PUTC+2
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; Sets GetC to the routine where HL points to and PutC to DE.
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stdioInit:
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ld (STDIO_GETC), hl
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ld (STDIO_PUTC), de
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ret
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stdioGetC:
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ld ix, (STDIO_GETC)
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jp (ix)
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stdioPutC:
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ld ix, (STDIO_PUTC)
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jp (ix)
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; print null-terminated string pointed to by HL
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printstr:
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push af
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push hl
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.loop:
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ld a, (hl) ; load character to send
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or a ; is it zero?
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jr z, .end ; if yes, we're finished
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call stdioPutC
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inc hl
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jr .loop
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.end:
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pop hl
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pop af
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ret
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; print A characters from string that HL points to
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printnstr:
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push bc
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push hl
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ld b, a
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.loop:
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ld a, (hl) ; load character to send
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call stdioPutC
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inc hl
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djnz .loop
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.end:
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pop hl
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pop bc
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ret
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printcrlf:
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ld a, ASCII_CR
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call stdioPutC
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ld a, ASCII_LF
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call stdioPutC
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ret
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; Print the hex char in A
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printHex:
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push af
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push hl
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ld hl, STDIO_HEX_FMT
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call fmtHexPair
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ld a, 2
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call printnstr
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pop hl
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pop af
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ret
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; Print the hex pair in HL
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printHexPair:
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push af
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ld a, h
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call printHex
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ld a, l
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call printHex
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pop af
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ret
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