mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-20 23:38:06 +11:00
a7ce9f6fc6
With fsGetC becoming a "random address" API, it broke pgm. This commit fixes it. To avoid adding the weight of a blkdev in pgm, I manage the read offset directly in pgm.
76 lines
2.2 KiB
NASM
76 lines
2.2 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.
|
|
; We can mutate it because the shell doesn't do anything with it afterwards.
|
|
pgmShellHook:
|
|
call fsIsOn
|
|
jr nz, .noFile
|
|
; first first space and replace it with zero so that we have something
|
|
; suitable for fsFindFN.
|
|
push hl ; remember beginning
|
|
ld a, ' '
|
|
call findchar
|
|
jr nz, .noarg ; if we have no arg, we want DE to point to the
|
|
; null char. Also, we have no replacement to
|
|
; make
|
|
; replace space with nullchar
|
|
xor a
|
|
ld (hl), a
|
|
inc hl ; make HL point to the beginning of args
|
|
.noarg:
|
|
ex de, hl ; DE now points to the beginning of args or to \0 if
|
|
; no args
|
|
pop hl ; HL points to cmdname, properly null-terminated
|
|
call fsFindFN
|
|
jr nz, .noFile
|
|
; We have a file! Load it and run it.
|
|
ex de, hl ; but first, make HL point to unparsed args.
|
|
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
|