shell/stdio: decouple from blkdev (again)

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.

kernel/blockdev.asm

@@ -150,7 +150,9 @@ blkGetC:
 blkGetCW:
 	ld	ix, (BLOCKDEV_GETC)
 .loop:
+	push	ix		; fs messes with IX a lot
 	call	callIX
+	pop	ix
 	jr	nz, .loop
 	ret
 

kernel/blockdev_cmds.asm

@@ -44,3 +44,60 @@ blkSeekCmd:
 	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
+blkLoadCmd:
+	.db	"load", 0b001, 0, 0
+blkLoad:
+	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
+blkSaveCmd:
+	.db	"save", 0b001, 0, 0
+blkSave:
+	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
+

kernel/shell.asm

@@ -22,7 +22,6 @@
 ; *** REQUIREMENTS ***
 ; parse
 ; stdio
-; blkdev
 
 ; *** DEFINES ***
 ; SHELL_EXTRA_CMD_COUNT: Number of extra cmds to be expected after the regular
@@ -32,7 +31,7 @@
 ; *** CONSTS ***
 
 ; number of entries in shellCmdTbl
-.equ	SHELL_CMD_COUNT		7+SHELL_EXTRA_CMD_COUNT
+.equ	SHELL_CMD_COUNT		6+SHELL_EXTRA_CMD_COUNT
 
 ; maximum number of bytes to receive as args in all commands. Determines the
 ; size of the args variable.
@@ -411,58 +410,29 @@ shellPeek:
 	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:
+; poke byte where memory pointer points and set them to bytes types through
+; stdioGetC. If the optional numerical byte arg is supplied, this number of
+; bytes will be expected from stdioGetC. Blocks until all bytes have been
+; fetched.
+shellPokeCmd:
+	.db	"poke", 0b101, 0, 0
+shellPoke:
 	push	bc
 	push	hl
 
 	ld	a, (hl)
+	or	a		; 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:  call	blkGetCW
-	jr	nz, .ioError
+.loop:	call	stdioGetC
+	jr	nz, .loop	; nothing typed? loop
 	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
@@ -530,6 +500,6 @@ shellIOWRCmd:
 ; 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 shellMptrCmd, shellPeekCmd, shellPokeCmd, shellCallCmd
 	.dw shellIORDCmd, shellIOWRCmd
 

kernel/stdio.asm

@@ -1,12 +1,9 @@
 ; stdio
 ;
-; Allows other modules to print to "standard out", that is, the console through
-; which the user is connected in a decoupled manner.
+; Allows other modules to print to "standard out", and get data from "stamdard
+; in", that is, the console through which the user is connected in a decoupled
+; manner.
 ;
-; *** REQUIREMENTS ***
-; blkdev. select the block device you want to use as stdio just before you call
-; stdioInit.
-
 ; *** VARIABLES ***
 ; Used to store formatted hex values just before printing it.
 .equ	STDIO_HEX_FMT	STDIO_RAMSTART
@@ -14,14 +11,10 @@
 .equ	STDIO_PUTC	STDIO_GETC+2
 .equ	STDIO_RAMEND	STDIO_PUTC+2
 
-; Select the blockdev to use as stdio before calling this.
+; Sets GetC to the routine where HL points to and PutC to DE.
 stdioInit:
-	push	hl
-	ld	hl, (BLOCKDEV_GETC)
 	ld	(STDIO_GETC), hl
-	ld	hl, (BLOCKDEV_PUTC)
-	ld	(STDIO_PUTC), hl
-	pop	hl
+	ld	(STDIO_PUTC), de
 	ret
 
 stdioGetC:

recipes/rc2014/glue.asm

@@ -16,13 +16,7 @@ jp	aciaInt
 .equ	ACIA_RAMSTART	RAMSTART
 #include "acia.asm"
 
-.equ	BLOCKDEV_RAMSTART	ACIA_RAMEND
-.equ	BLOCKDEV_COUNT		1
-#include "blockdev.asm"
-; List of devices
-.dw	aciaGetC, aciaPutC, 0, 0
-
-.equ	STDIO_RAMSTART	BLOCKDEV_RAMEND
+.equ	STDIO_RAMSTART	ACIA_RAMEND
 #include "stdio.asm"
 
 .equ	SHELL_RAMSTART	STDIO_RAMEND
@@ -37,9 +31,8 @@ init:
 	im 1
 
 	call	aciaInit
-	xor	a
-	ld	de, BLOCKDEV_GETC
-	call	blkSel
+	ld	hl, aciaGetC
+	ld	de, aciaPutC
 	call	stdioInit
 	call	shellInit
 	ei

tools/emul/shell/shell_.asm

@@ -17,10 +17,9 @@
 #include "parse.asm"
 
 .equ	BLOCKDEV_RAMSTART	RAMSTART
-.equ	BLOCKDEV_COUNT		4
+.equ	BLOCKDEV_COUNT		3
 #include "blockdev.asm"
 ; List of devices
-.dw	emulGetC, emulPutC, 0, 0
 .dw	fsdevGetC, fsdevPutC, fsdevSeek, fsdevTell
 .dw	stdoutGetC, stdoutPutC, stdoutSeek, stdoutTell
 .dw	stdinGetC, stdinPutC, stdinSeek, stdinTell
@@ -36,9 +35,10 @@
 #include "fs_cmds.asm"
 
 .equ	SHELL_RAMSTART		FS_RAMEND
-.equ	SHELL_EXTRA_CMD_COUNT	7
+.equ	SHELL_EXTRA_CMD_COUNT	9
 #include "shell.asm"
-.dw	blkBselCmd, blkSeekCmd, fsOnCmd, flsCmd, fnewCmd, fdelCmd, fopnCmd
+.dw	blkBselCmd, blkSeekCmd, blkLoadCmd, blkSaveCmd
+.dw	fsOnCmd, flsCmd, fnewCmd, fdelCmd, fopnCmd
 
 .equ	PGM_CODEADDR		USERCODE
 #include "pgm.asm"
@@ -48,18 +48,14 @@ init:
 	; setup stack
 	ld	hl, KERNEL_RAMEND
 	ld	sp, hl
-	xor	a
-	ld	de, BLOCKDEV_GETC
-	call	blkSel
+	ld	hl, emulGetC
+	ld	de, emulPutC
 	call	stdioInit
 	call	fsInit
-	ld	a, 1	; select fsdev
+	ld	a, 0	; select fsdev
 	ld	de, BLOCKDEV_GETC
 	call	blkSel
 	call	fsOn
-	xor	a	; select ACIA
-	ld	de, BLOCKDEV_GETC
-	call	blkSel
 	call	shellInit
 	ld	hl, pgmShellHook
 	ld	(SHELL_CMDHOOK), hl

tools/upload.py

@@ -32,8 +32,8 @@ def main():
         print("File too big. 0xff bytes max")
         return 1
     fd = os.open(args.device, os.O_RDWR)
-    sendcmd(fd, 'load {:x}'.format(st.st_size).encode())
-    print("Loading...")
+    sendcmd(fd, 'poke {:x}'.format(st.st_size).encode())
+    print("Poking...")
     with open(args.filename, 'rb') as fp:
         fcontents = fp.read()
         for c in fcontents:
@@ -41,7 +41,7 @@ def main():
             # Let's give the machine a bit of time to breathe. We ain't in a
             # hurry now, are we?
             time.sleep(0.0001)
-    print("Loaded")
+    print("Poked")
     os.read(fd, 5)
     print("Peeking back...")
     sendcmd(fd, 'peek {:x}'.format(st.st_size).encode())