diff --git a/doc/glue-code.md b/doc/glue-code.md
index 54404a7..a1498bc 100644
--- a/doc/glue-code.md
+++ b/doc/glue-code.md
@@ -25,17 +25,27 @@ look like:
ld sp, hl
im 1
call aciaInit
- call shellInit
+ xor a
+ ld de, BLOCKDEV_GETC
+ call blkSel
+ call stdioInit
+ call shellInit
ei
- jp shellLoop
+ jp shellLoop
#include "core.asm"
.equ ACIA_RAMSTART RAMSTART
#include "acia.asm"
- .equ SHELL_RAMSTART ACIA_RAMEND
- .define SHELL_GETC call aciaGetC
- .define SHELL_PUTC call aciaPutC
- .define SHELL_IO_GETC call aciaGetC
+ .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
+ #include "stdio.asm"
+
+ .equ SHELL_RAMSTART STDIO_RAMEND
.equ SHELL_EXTRA_CMD_COUNT 0
#include "shell.asm"
diff --git a/kernel/pgm.asm b/kernel/pgm.asm
new file mode 100644
index 0000000..ead37ac
--- /dev/null
+++ b/kernel/pgm.asm
@@ -0,0 +1,61 @@
+; 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.
+;
+; *** Defines ***
+; PGM_CODEADDR: Memory address where to place the code we load.
+
+; 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.
+ 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.
+pgmRun:
+ call fsIsValid
+ jr nz, .ioError
+ ld ix, FS_HANDLES
+ call fsOpen
+ ld hl, PGM_CODEADDR
+.loop:
+ call fsGetC ; we use Z at end of loop
+ ld (hl), a ; Z preserved
+ inc hl ; Z preserved in 16-bit
+ jr z, .loop
+ ; ready to jump!
+ jp PGM_CODEADDR
+
+.ioError:
+ ld a, SHELL_ERR_IO_ERROR
+ ret
diff --git a/kernel/shell.asm b/kernel/shell.asm
index 2d49f63..3f6c28e 100644
--- a/kernel/shell.asm
+++ b/kernel/shell.asm
@@ -2,11 +2,17 @@
;
; 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.
+; The shell 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.
+; To determine the correct routine to call we first go through cmds in
+; shellCmdTbl. This means that we first go through internal cmds, then cmds
+; "grafted" by glue code.
+;
+; If the command isn't found, SHELL_CMDHOOK is called, which should set A to
+; zero if it executes something. Otherwise, SHELL_ERR_UNKNOWN_CMD will be
+; returned.
;
; See constants below for error codes.
;
@@ -59,7 +65,10 @@
; 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
+; Pointer to a hook to call when a cmd name isn't found
+.equ SHELL_CMDHOOK SHELL_BUF+SHELL_BUFSIZE
+
+.equ SHELL_RAMEND SHELL_CMDHOOK+2
; *** CODE ***
shellInit:
@@ -67,11 +76,12 @@ shellInit:
ld (SHELL_MEM_PTR), a
ld (SHELL_MEM_PTR+1), a
ld (SHELL_BUF), a
+ ld hl, noop
+ ld (SHELL_CMDHOOK), hl
; print welcome
ld hl, .welcome
- call printstr
- ret
+ jp printstr ; returns
.welcome:
.db "Collapse OS", ASCII_CR, ASCII_LF, "> ", 0
@@ -154,6 +164,12 @@ shellParse:
; exhausted loop? not found
ld a, SHELL_ERR_UNKNOWN_CMD
+ ; Before erroring out, let's try SHELL_HOOK.
+ ld ix, (SHELL_CMDHOOK)
+ call callIX
+ jr z, .end ; oh, not an error!
+ ; still an error. Might be different than SHELL_ERR_UNKNOWN_CMD though.
+ ; maybe a routine was called, but errored out.
jr .error
.found:
@@ -171,7 +187,7 @@ shellParse:
; We're ready to parse args
call shellParseArgs
- cp 0
+ or a ; cp 0
jr nz, .parseerror
ld hl, SHELL_CMD_ARGS
@@ -182,7 +198,7 @@ shellParse:
push de \ pop ix
; Ready to roll!
call callIX
- cp 0
+ or a ; cp 0
jr nz, .error ; if A is non-zero, we have an error
jr .end
diff --git a/recipes/rc2014/glue.asm b/recipes/rc2014/glue.asm
index 77fba48..7a55b04 100644
--- a/recipes/rc2014/glue.asm
+++ b/recipes/rc2014/glue.asm
@@ -26,7 +26,7 @@ jp aciaInt
#include "stdio.asm"
.equ SHELL_RAMSTART STDIO_RAMEND
-.equ SHELL_EXTRA_CMD_COUNT 0
+.equ SHELL_EXTRA_CMD_COUNT 0
#include "shell.asm"
init:
diff --git a/recipes/rc2014/sdcard/README.md b/recipes/rc2014/sdcard/README.md
index fd07d6c..38121d2 100644
--- a/recipes/rc2014/sdcard/README.md
+++ b/recipes/rc2014/sdcard/README.md
@@ -107,22 +107,21 @@ filesystem into the `sdcard.cfs` file. That can be mounted by Collapse OS!
Then, you insert your SD card in your SPI relay and go:
- Collapse OS
- > mptr 9000
- 9000
- > sdci
- > bsel 1
- > fson
- > fls
- helo
- hello.txt
- > fopn 0 helo
- > load 10
- > peek 10
- 210690C3030048656C6C6F210D0A0000
- > call 00 0000
- Hello!
- >
+ Collapse OS
+ > sdci
+ > bsel 1
+ > fson
+ > fls
+ helo
+ hello.txt
+ > helo
+ Hello!
+ >
+
+The `helo` command is a bit magical and is due to the hook implemented in
+`pgm.asm`: when an unknown command is typed, it looks in the currently mounted
+filesystem for a file with the same name. If it finds it, it loads it in memory
+at a predefined place (in our case, `0x9000`) and executes it.
Now let that sink in for a minute. You've just mounted a filesystem on a SD
card, loaded a file from it in memory and executed that file, all that on a
diff --git a/recipes/rc2014/sdcard/glue.asm b/recipes/rc2014/sdcard/glue.asm
index 8d613ed..fb3b103 100644
--- a/recipes/rc2014/sdcard/glue.asm
+++ b/recipes/rc2014/sdcard/glue.asm
@@ -2,6 +2,7 @@
; The RAM module is selected on A15, so it has the range 0x8000-0xffff
.equ RAMSTART 0x8000
.equ RAMEND 0xffff
+.equ PGM_CODEADDR 0x9000
.equ ACIA_CTL 0x80 ; Control and status. RS off.
.equ ACIA_IO 0x81 ; Transmit. RS on.
@@ -46,10 +47,12 @@ jp aciaInt
.dw sdcInitializeCmd, blkBselCmd, blkSeekCmd
.dw fsOnCmd, flsCmd, fnewCmd, fdelCmd, fopnCmd
-.equ SDC_RAMSTART SHELL_RAMEND
-.equ SDC_PORT_CSHIGH 6
-.equ SDC_PORT_CSLOW 5
-.equ SDC_PORT_SPI 4
+#include "pgm.asm"
+
+.equ SDC_RAMSTART SHELL_RAMEND
+.equ SDC_PORT_CSHIGH 6
+.equ SDC_PORT_CSLOW 5
+.equ SDC_PORT_SPI 4
#include "sdc.asm"
init:
@@ -64,6 +67,8 @@ init:
call blkSel
call stdioInit
call shellInit
+ ld hl, pgmShellHook
+ ld (SHELL_CMDHOOK), hl
ei
jp shellLoop
diff --git a/recipes/rc2014/sdcard/helo.asm b/recipes/rc2014/sdcard/helo.asm
index 0c905b3..58b71c7 100644
--- a/recipes/rc2014/sdcard/helo.asm
+++ b/recipes/rc2014/sdcard/helo.asm
@@ -4,7 +4,9 @@
.org 0x9000
ld hl, sHello
- jp printstr ; return
+ call printstr
+ xor a ; success
+ ret
sHello:
.db "Hello!", 0x0d, 0x0a, 0
diff --git a/tools/emul/shell/shell_.asm b/tools/emul/shell/shell_.asm
index 1dad3d7..26d02c5 100644
--- a/tools/emul/shell/shell_.asm
+++ b/tools/emul/shell/shell_.asm
@@ -1,6 +1,7 @@
; named shell_.asm to avoid infinite include loop.
.equ RAMSTART 0x4000
-.equ RAMEND 0x5000
+.equ KERNEL_RAMEND 0x5000
+.equ USERCODE 0x9000
.equ STDIO_PORT 0x00
.equ FS_DATA_PORT 0x01
.equ FS_SEEKL_PORT 0x02
@@ -9,6 +10,9 @@
jp init
+; *** JUMP TABLE ***
+ jp printstr
+
#include "core.asm"
#include "parse.asm"
@@ -36,10 +40,13 @@
#include "shell.asm"
.dw blkBselCmd, blkSeekCmd, fsOnCmd, flsCmd, fnewCmd, fdelCmd, fopnCmd
+.equ PGM_CODEADDR USERCODE
+#include "pgm.asm"
+
init:
di
; setup stack
- ld hl, RAMEND
+ ld hl, KERNEL_RAMEND
ld sp, hl
xor a
ld de, BLOCKDEV_GETC
@@ -54,6 +61,8 @@ init:
ld de, BLOCKDEV_GETC
call blkSel
call shellInit
+ ld hl, pgmShellHook
+ ld (SHELL_CMDHOOK), hl
jp shellLoop
emulGetC: