mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-30 22:38:09 +11:00
519 lines
12 KiB
NASM
519 lines
12 KiB
NASM
; shell
|
|
;
|
|
; Runs a shell over a block device interface.
|
|
|
|
; Status: incomplete. As it is now, it spits a welcome prompt, wait for input
|
|
; and compare the first 4 chars of the input with a command table and call the
|
|
; appropriate routine if it's found, an error if it's not.
|
|
;
|
|
; Commands, for now, are partially implemented.
|
|
;
|
|
; See constants below for error codes.
|
|
;
|
|
; All numerical values in the Collapse OS shell are represented and parsed in
|
|
; hexadecimal form, without prefix or suffix.
|
|
|
|
; *** REQUIREMENTS ***
|
|
; parse
|
|
; stdio
|
|
; blkdev
|
|
|
|
; *** DEFINES ***
|
|
; SHELL_EXTRA_CMD_COUNT: Number of extra cmds to be expected after the regular
|
|
; ones. See comment in COMMANDS section for details.
|
|
; SHELL_RAMSTART
|
|
|
|
; *** CONSTS ***
|
|
|
|
; number of entries in shellCmdTbl
|
|
.equ SHELL_CMD_COUNT 7+SHELL_EXTRA_CMD_COUNT
|
|
|
|
; maximum number of bytes to receive as args in all commands. Determines the
|
|
; size of the args variable.
|
|
.equ SHELL_CMD_ARGS_MAXSIZE 3
|
|
|
|
; The command that was type isn't known to the shell
|
|
.equ SHELL_ERR_UNKNOWN_CMD 0x01
|
|
|
|
; Arguments for the command weren't properly formatted
|
|
.equ SHELL_ERR_BAD_ARGS 0x02
|
|
|
|
; IO routines (GetC, PutC) returned an error in a load/save command
|
|
.equ SHELL_ERR_IO_ERROR 0x05
|
|
|
|
; Size of the shell command buffer. If a typed command reaches this size, the
|
|
; command is flushed immediately (same as pressing return).
|
|
.equ SHELL_BUFSIZE 0x20
|
|
|
|
; *** VARIABLES ***
|
|
; Memory address that the shell is currently "pointing at" for peek, load, call
|
|
; operations. Set with mptr.
|
|
.equ SHELL_MEM_PTR SHELL_RAMSTART
|
|
|
|
; Places where we store arguments specifiers and where resulting values are
|
|
; written to after parsing.
|
|
.equ SHELL_CMD_ARGS SHELL_MEM_PTR+2
|
|
|
|
; Command buffer. We read types chars into this buffer until return is pressed
|
|
; This buffer is null-terminated and we don't keep an index around: we look
|
|
; for the null-termination every time we write to it. Simpler that way.
|
|
.equ SHELL_BUF SHELL_CMD_ARGS+SHELL_CMD_ARGS_MAXSIZE
|
|
|
|
.equ SHELL_RAMEND SHELL_BUF+SHELL_BUFSIZE
|
|
|
|
; *** CODE ***
|
|
shellInit:
|
|
xor a
|
|
ld (SHELL_MEM_PTR), a
|
|
ld (SHELL_BUF), a
|
|
|
|
; print welcome
|
|
ld hl, .welcome
|
|
call printstr
|
|
ret
|
|
|
|
.welcome:
|
|
.db "Collapse OS", ASCII_CR, ASCII_LF, "> ", 0
|
|
|
|
; Inifite loop that processes input. Because it's infinite, you should jump
|
|
; to it rather than call it. Saves two precious bytes in the stack.
|
|
shellLoop:
|
|
; First, let's wait until something is typed.
|
|
call stdioGetC
|
|
jr nz, shellLoop ; nothing typed? loop
|
|
; got it. Now, is it a CR or LF?
|
|
cp ASCII_CR
|
|
jr z, .do ; char is CR? do!
|
|
cp ASCII_LF
|
|
jr z, .do ; char is LF? do!
|
|
|
|
; Echo the received character right away so that we see what we type
|
|
call stdioPutC
|
|
|
|
; Ok, gotta add it do the buffer
|
|
; save char for later
|
|
ex af, af'
|
|
ld hl, SHELL_BUF
|
|
xor a ; look for null
|
|
call findchar ; HL points to where we need to write
|
|
; A is the number of chars in the buf
|
|
cp SHELL_BUFSIZE
|
|
jr z, .do ; A == bufsize? then our buffer is full. do!
|
|
|
|
; bring the char back in A
|
|
ex af, af'
|
|
; Buffer not full, not CR or LF. Let's put that char in our buffer and
|
|
; read again.
|
|
ld (hl), a
|
|
; Now, write a zero to the next byte to properly terminate our string.
|
|
inc hl
|
|
xor a
|
|
ld (hl), a
|
|
|
|
jr shellLoop
|
|
|
|
.do:
|
|
call printcrlf
|
|
ld hl, SHELL_BUF
|
|
call shellParse
|
|
; empty our buffer by writing a zero to its first char
|
|
xor a
|
|
ld (hl), a
|
|
|
|
ld hl, .prompt
|
|
call printstr
|
|
jr shellLoop
|
|
; no ret because we never return
|
|
|
|
.prompt:
|
|
.db "> ", 0
|
|
|
|
; Parse command (null terminated) at HL and calls it
|
|
shellParse:
|
|
push af
|
|
push bc
|
|
push de
|
|
push hl
|
|
push ix
|
|
|
|
ld de, shellCmdTbl
|
|
ld a, SHELL_CMD_COUNT
|
|
ld b, a
|
|
|
|
.loop:
|
|
push de ; we need to keep that table entry around...
|
|
call intoDE ; Jump from the table entry to the cmd addr.
|
|
ld a, 4 ; 4 chars to compare
|
|
call strncmp
|
|
pop de
|
|
jr z, .found
|
|
inc de
|
|
inc de
|
|
djnz .loop
|
|
|
|
; exhausted loop? not found
|
|
ld a, SHELL_ERR_UNKNOWN_CMD
|
|
jr .error
|
|
|
|
.found:
|
|
; we found our command. DE points to its table entry. Now, let's parse
|
|
; our args.
|
|
call intoDE ; Jump from the table entry to the cmd addr.
|
|
|
|
; advance the HL pointer to the beginning of the args.
|
|
ld a, ' '
|
|
call findchar
|
|
|
|
; Now, let's have DE point to the argspecs
|
|
ld a, 4
|
|
call addDE
|
|
|
|
; We're ready to parse args
|
|
call shellParseArgs
|
|
cp 0
|
|
jr nz, .parseerror
|
|
|
|
ld hl, SHELL_CMD_ARGS
|
|
; Args parsed, now we can load the routine address and call it.
|
|
; let's have DE point to the jump line
|
|
ld a, SHELL_CMD_ARGS_MAXSIZE
|
|
call addDE
|
|
push ix \ pop de
|
|
; Ready to roll!
|
|
call callIX
|
|
cp 0
|
|
jr nz, .error ; if A is non-zero, we have an error
|
|
jr .end
|
|
|
|
.parseerror:
|
|
ld a, SHELL_ERR_BAD_ARGS
|
|
.error:
|
|
call shellPrintErr
|
|
.end:
|
|
pop ix
|
|
pop hl
|
|
pop de
|
|
pop bc
|
|
pop af
|
|
ret
|
|
|
|
; Print the error code set in A (in hex)
|
|
shellPrintErr:
|
|
push af
|
|
push hl
|
|
|
|
ld hl, .str
|
|
call printstr
|
|
call printHex
|
|
call printcrlf
|
|
|
|
pop hl
|
|
pop af
|
|
ret
|
|
|
|
.str:
|
|
.db "ERR ", 0
|
|
|
|
; Parse arguments at (HL) with specifiers at (DE) into (SHELL_CMD_ARGS).
|
|
; (HL) should point to the character *just* after the name of the command
|
|
; because we verify, in the case that we have args, that we have a space there.
|
|
;
|
|
; Args specifiers are a series of flag for each arg:
|
|
; Bit 0 - arg present: if unset, we stop parsing there
|
|
; Bit 1 - is word: this arg is a word rather than a byte. Because our
|
|
; destination are bytes anyway, this doesn't change much except
|
|
; for whether we expect a space between the hex pairs. If set,
|
|
; you still need to have a specifier for the second part of
|
|
; the multibyte.
|
|
; Bit 2 - optional: If set and not present during parsing, we don't error out
|
|
; and write zero
|
|
;
|
|
; Bit 3 - String argument: If set, this argument is a string. A pointer to the
|
|
; read string, null terminated (max 0x20 chars) will
|
|
; be placed in the next two bytes. This has to be the
|
|
; last argument of the list and it stops parsing.
|
|
; Sets A to nonzero if there was an error during parsing, zero otherwise.
|
|
; If there was an error during parsing, carry is set.
|
|
shellParseArgs:
|
|
push bc
|
|
push de
|
|
push hl
|
|
push ix
|
|
|
|
ld ix, SHELL_CMD_ARGS
|
|
ld a, SHELL_CMD_ARGS_MAXSIZE
|
|
ld b, a
|
|
xor c
|
|
.loop:
|
|
; init the arg value to a default 0
|
|
xor a
|
|
ld (ix), a
|
|
|
|
ld a, (hl)
|
|
; is this the end of the line?
|
|
cp 0
|
|
jr z, .endofargs
|
|
|
|
; do we have a proper space char?
|
|
cp ' '
|
|
jr z, .hasspace ; We're fine
|
|
|
|
; is our previous arg a multibyte? (argspec still in C)
|
|
bit 1, c
|
|
jr z, .error ; bit not set? error
|
|
dec hl ; offset the "inc hl" below
|
|
|
|
.hasspace:
|
|
; Get the specs
|
|
ld a, (de)
|
|
bit 0, a ; do we have an arg?
|
|
jr z, .error ; not set? then we have too many args
|
|
ld c, a ; save the specs for the next loop
|
|
inc hl ; (hl) points to a space, go next
|
|
bit 3, a ; is our arg a string?
|
|
jr z, .notAString
|
|
; our arg is a string. Let's place HL in our next two bytes and call
|
|
; it a day. Little endian, remember
|
|
ld (ix), l
|
|
ld (ix+1), h
|
|
jr .success ; directly to success: skip endofargs checks
|
|
.notAString:
|
|
call parseHexPair
|
|
jr c, .error
|
|
; we have a good arg and we need to write A in (IX).
|
|
ld (ix), a
|
|
|
|
; Good! increase counters
|
|
inc de
|
|
inc ix
|
|
inc hl ; get to following char (generally a space)
|
|
djnz .loop
|
|
; If we get here, it means that our next char *has* to be a null char
|
|
ld a, (hl)
|
|
cp 0
|
|
jr z, .success ; zero? great!
|
|
jr .error
|
|
|
|
.endofargs:
|
|
; We encountered our null char. Let's verify that we either have no
|
|
; more args or that they are optional
|
|
ld a, (de)
|
|
cp 0
|
|
jr z, .success ; no arg? success
|
|
bit 2, a
|
|
jr nz, .success ; if set, arg is optional. success
|
|
jr .error
|
|
|
|
.success:
|
|
xor a
|
|
jr .end
|
|
.error:
|
|
inc a
|
|
.end:
|
|
pop ix
|
|
pop hl
|
|
pop de
|
|
pop bc
|
|
ret
|
|
|
|
; *** COMMANDS ***
|
|
; A command is a 4 char names, followed by a SHELL_CMD_ARGS_MAXSIZE bytes of
|
|
; argument specs, followed by the routine. Then, a simple table of addresses
|
|
; is compiled in a block and this is what is iterated upon when we want all
|
|
; available commands.
|
|
;
|
|
; Format: 4 bytes name followed by SHELL_CMD_ARGS_MAXSIZE bytes specifiers,
|
|
; followed by 3 bytes jump. fill names with zeroes
|
|
;
|
|
; When these commands are called, HL points to the first byte of the
|
|
; parsed command args.
|
|
;
|
|
; If the command is a success, it should set A to zero. If the command results
|
|
; in an error, it should set an error code in A.
|
|
;
|
|
; Extra commands: Other parts might define new commands. You can add these
|
|
; commands to your shell. First, set SHELL_EXTRA_CMD_COUNT to
|
|
; the number of extra commands to add, then add a ".dw"
|
|
; directive *just* after your '#include "shell.asm"'. Voila!
|
|
;
|
|
|
|
; Set memory pointer to the specified address (word).
|
|
; Example: mptr 01fe
|
|
shellMptrCmd:
|
|
.db "mptr", 0b011, 0b001, 0
|
|
shellMptr:
|
|
push hl
|
|
|
|
; reminder: z80 is little-endian
|
|
ld a, (hl)
|
|
ld (SHELL_MEM_PTR+1), a
|
|
inc hl
|
|
ld a, (hl)
|
|
ld (SHELL_MEM_PTR), a
|
|
|
|
ld hl, (SHELL_MEM_PTR)
|
|
ld a, h
|
|
call printHex
|
|
ld a, l
|
|
call printHex
|
|
call printcrlf
|
|
|
|
pop hl
|
|
xor a
|
|
ret
|
|
|
|
|
|
; peek byte where memory pointer points to any display its value. If the
|
|
; optional numerical byte arg is supplied, this number of bytes will be printed
|
|
;
|
|
; Example: peek 2 (will print 2 bytes)
|
|
shellPeekCmd:
|
|
.db "peek", 0b101, 0, 0
|
|
shellPeek:
|
|
push bc
|
|
push de
|
|
push hl
|
|
|
|
ld a, (hl)
|
|
cp 0
|
|
jr nz, .arg1isset ; if arg1 is set, no need for a default
|
|
ld a, 1 ; default for arg1
|
|
.arg1isset:
|
|
ld b, a
|
|
ld hl, (SHELL_MEM_PTR)
|
|
.loop: ld a, (hl)
|
|
call printHex
|
|
inc hl
|
|
djnz .loop
|
|
call printcrlf
|
|
|
|
.end:
|
|
pop hl
|
|
pop de
|
|
pop bc
|
|
xor a
|
|
ret
|
|
|
|
; Load the specified number of bytes (max 0xff) from IO and write them in the
|
|
; current memory pointer (which doesn't change). This gets chars from
|
|
; blkGetCW.
|
|
; Control is returned to the shell only after all bytes are read.
|
|
;
|
|
; Example: load 42
|
|
shellLoadCmd:
|
|
.db "load", 0b001, 0, 0
|
|
shellLoad:
|
|
push bc
|
|
push hl
|
|
|
|
ld a, (hl)
|
|
ld b, a
|
|
ld hl, (SHELL_MEM_PTR)
|
|
.loop: call blkGetCW
|
|
jr nz, .ioError
|
|
ld (hl), a
|
|
inc hl
|
|
djnz .loop
|
|
; success
|
|
xor a
|
|
jr .end
|
|
.ioError:
|
|
ld a, SHELL_ERR_IO_ERROR
|
|
.end:
|
|
pop hl
|
|
pop bc
|
|
ret
|
|
|
|
; Load the specified number of bytes (max 0xff) from the current memory pointer
|
|
; and write them to I/O. Memory pointer doesn't move. This puts chars to
|
|
; blkPutC.
|
|
; Control is returned to the shell only after all bytes are written.
|
|
;
|
|
; Example: save 42
|
|
shellSaveCmd:
|
|
.db "save", 0b001, 0, 0
|
|
shellSave:
|
|
push bc
|
|
push hl
|
|
|
|
ld a, (hl)
|
|
ld b, a
|
|
ld hl, (SHELL_MEM_PTR)
|
|
.loop:
|
|
ld a, (hl)
|
|
inc hl
|
|
call blkPutC
|
|
djnz .loop
|
|
|
|
.end:
|
|
pop hl
|
|
pop bc
|
|
xor a
|
|
ret
|
|
|
|
; Calls the routine where the memory pointer currently points. This can take two
|
|
; parameters, A and HL. The first one is a byte, the second, a word. These are
|
|
; the values that A and HL are going to be set to just before calling.
|
|
; Example: run 42 cafe
|
|
shellCallCmd:
|
|
.db "call", 0b101, 0b111, 0b001
|
|
shellCall:
|
|
push hl
|
|
push ix
|
|
|
|
; Let's recap here. At this point, we have:
|
|
; 1. The address we want to execute in (SHELL_MEM_PTR)
|
|
; 2. our A arg as the first byte of (HL)
|
|
; 2. our HL arg as (HL+1) and (HL+2)
|
|
; Ready, set, go!
|
|
ld ix, (SHELL_MEM_PTR)
|
|
ld a, (hl)
|
|
ex af, af'
|
|
inc hl
|
|
ld a, (hl)
|
|
exx
|
|
ld h, a
|
|
exx
|
|
inc hl
|
|
ld a, (hl)
|
|
exx
|
|
ld l, a
|
|
ex af, af'
|
|
call callIX
|
|
|
|
.end:
|
|
pop ix
|
|
pop hl
|
|
xor a
|
|
ret
|
|
|
|
shellIORDCmd:
|
|
.db "iord", 0b001, 0, 0
|
|
push bc
|
|
ld a, (hl)
|
|
ld c, a
|
|
in a, (c)
|
|
call printHex
|
|
xor a
|
|
pop bc
|
|
ret
|
|
|
|
shellIOWRCmd:
|
|
.db "iowr", 0b001, 0b001, 0
|
|
push bc
|
|
ld a, (hl)
|
|
ld c, a
|
|
inc hl
|
|
ld a, (hl)
|
|
out (c), a
|
|
xor a
|
|
pop bc
|
|
ret
|
|
|
|
; This table is at the very end of the file on purpose. The idea is to be able
|
|
; to graft extra commands easily after an include in the glue file.
|
|
shellCmdTbl:
|
|
.dw shellMptrCmd, shellPeekCmd, shellLoadCmd, shellSaveCmd, shellCallCmd
|
|
.dw shellIORDCmd, shellIOWRCmd
|
|
|