mirror of https://github.com/hsoft/collapseos.git
64 lines
1.7 KiB
NASM
64 lines
1.7 KiB
NASM
; pgm - execute programs loaded from filesystem
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;
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; Implements a shell hook that searches the filesystem for a file with the same
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; name as the cmd, loads that file in memory and executes it, sending the
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; program a pointer to *unparsed* arguments in HL.
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;
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; We expect the loaded program to return a status code in A. 0 means success,
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; non-zero means error. Programs should avoid having error code overlaps with
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; the shell so that we know where the error comes from.
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;
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; *** Requirements ***
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; fs
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;
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; *** Defines ***
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; PGM_CODEADDR: Memory address where to place the code we load.
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;
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; *** Variables ***
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.equ PGM_HANDLE PGM_RAMSTART
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.equ PGM_RAMEND @+FS_HANDLE_SIZE
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; Routine suitable to plug into SHELL_CMDHOOK. HL points to the full cmdline.
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; which has been processed to replace the first ' ' with a null char.
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pgmShellHook:
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call fsIsOn
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jr nz, .noFile
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; (HL) is suitable for a direct fsFindFN call
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call fsFindFN
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jr nz, .noFile
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; We have a file! Advance HL to args
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xor a
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call findchar
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inc hl ; beginning of args
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; Alright, ready to run!
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jp pgmRun
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.noFile:
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ld a, SHELL_ERR_IO_ERROR
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ret
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; Loads code in file that FS_PTR is currently pointing at and place it in
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; PGM_CODEADDR. Then, jump to PGM_CODEADDR. We expect HL to point to unparsed
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; arguments being given to the program.
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pgmRun:
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call fsIsValid
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jr nz, .ioError
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push hl ; unparsed args
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ld ix, PGM_HANDLE
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call fsOpen
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ld hl, 0 ; addr that we read in file handle
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ld de, PGM_CODEADDR ; addr in mem we write to
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.loop:
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call fsGetB ; we use Z at end of loop
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ld (de), a ; Z preserved
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inc hl ; Z preserved in 16-bit
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inc de ; Z preserved in 16-bit
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jr z, .loop
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pop hl ; recall args
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; ready to jump!
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jp PGM_CODEADDR
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.ioError:
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ld a, SHELL_ERR_IO_ERROR
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ret
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