mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-08 17:38:04 +11:00
64 lines
1.7 KiB
NASM
64 lines
1.7 KiB
NASM
; pgm - execute programs loaded from filesystem
|
|
;
|
|
; Implements a shell hook that searches the filesystem for a file with the same
|
|
; name as the cmd, loads that file in memory and executes it, sending the
|
|
; program a pointer to *unparsed* arguments in HL.
|
|
;
|
|
; We expect the loaded program to return a status code in A. 0 means success,
|
|
; non-zero means error. Programs should avoid having error code overlaps with
|
|
; the shell so that we know where the error comes from.
|
|
;
|
|
; *** Requirements ***
|
|
; fs
|
|
;
|
|
; *** Defines ***
|
|
; PGM_CODEADDR: Memory address where to place the code we load.
|
|
;
|
|
; *** Variables ***
|
|
.equ PGM_HANDLE PGM_RAMSTART
|
|
.equ PGM_RAMEND PGM_HANDLE+FS_HANDLE_SIZE
|
|
|
|
; Routine suitable to plug into SHELL_CMDHOOK. HL points to the full cmdline.
|
|
; which has been processed to replace the first ' ' with a null char.
|
|
pgmShellHook:
|
|
call fsIsOn
|
|
jr nz, .noFile
|
|
; (HL) is suitable for a direct fsFindFN call
|
|
call fsFindFN
|
|
jr nz, .noFile
|
|
; We have a file! Advance HL to args
|
|
xor a
|
|
call findchar
|
|
inc hl ; beginning of args
|
|
; Alright, ready to run!
|
|
jp pgmRun
|
|
.noFile:
|
|
ld a, SHELL_ERR_IO_ERROR
|
|
ret
|
|
|
|
; Loads code in file that FS_PTR is currently pointing at and place it in
|
|
; PGM_CODEADDR. Then, jump to PGM_CODEADDR. We expect HL to point to unparsed
|
|
; arguments being given to the program.
|
|
pgmRun:
|
|
call fsIsValid
|
|
jr nz, .ioError
|
|
push hl ; unparsed args
|
|
ld ix, PGM_HANDLE
|
|
call fsOpen
|
|
ld hl, 0 ; addr that we read in file handle
|
|
ld de, PGM_CODEADDR ; addr in mem we write to
|
|
.loop:
|
|
call fsGetC ; we use Z at end of loop
|
|
ld (de), a ; Z preserved
|
|
inc hl ; Z preserved in 16-bit
|
|
inc de ; Z preserved in 16-bit
|
|
jr z, .loop
|
|
|
|
pop hl ; recall args
|
|
; ready to jump!
|
|
jp PGM_CODEADDR
|
|
|
|
.ioError:
|
|
ld a, SHELL_ERR_IO_ERROR
|
|
ret
|