mirror of
https://github.com/hsoft/collapseos.git
synced 2024-12-25 05:08:05 +11:00
basic: begin an implementation from sratch
Let's see where it will lead us...
This commit is contained in:
parent
1ae51bea3a
commit
f3992ed598
@ -18,3 +18,10 @@ HL to a pointer to unparsed arguments in string form, null terminated.
|
||||
|
||||
The userspace application is expected to set A on return. 0 means success,
|
||||
non-zero means error.
|
||||
|
||||
A userspace application can expect the `SP` pointer to be properly set. If it
|
||||
moves it, it should take care of returning it where it was before returning
|
||||
because otherwise, it will break the kernel.
|
||||
|
||||
Apps in Collapse OS are design to be ROM-compatible, that is, they don't write
|
||||
to addresses that are part of the code's address space.
|
||||
|
16
apps/basic/README.md
Normal file
16
apps/basic/README.md
Normal file
@ -0,0 +1,16 @@
|
||||
# basic
|
||||
|
||||
**Work in progress, not finished.**
|
||||
|
||||
This is a BASIC interpreter which is being written from scratch for Collapse OS.
|
||||
There are many existing z80 implementations around, some of them open source
|
||||
and most of them good and efficient, but because a lot of that code overlaps
|
||||
with code that has already been written for zasm, I believe that it's better to
|
||||
reuse those bits of code.
|
||||
|
||||
Integrating an existing BASIC to Collapse OS seemed a bigger challenge than
|
||||
writing from scratch, so here I am, writing from scratch again...
|
||||
|
||||
The biggest challenge here is to extract code from zasm, adapt it to fit BASIC,
|
||||
not break anything, and have the wisdom to see when copy/pasting is a better
|
||||
idea.
|
17
apps/basic/glue.asm
Normal file
17
apps/basic/glue.asm
Normal file
@ -0,0 +1,17 @@
|
||||
; *** Requirements ***
|
||||
; addHL
|
||||
; printstr
|
||||
; printcrlf
|
||||
; stdioReadLine
|
||||
; strncmp
|
||||
;
|
||||
.inc "user.h"
|
||||
|
||||
.inc "err.h"
|
||||
.org USER_CODE
|
||||
|
||||
jp basStart
|
||||
|
||||
.inc "lib/parse.asm"
|
||||
.equ BAS_RAMSTART USER_RAMSTART
|
||||
.inc "basic/main.asm"
|
87
apps/basic/main.asm
Normal file
87
apps/basic/main.asm
Normal file
@ -0,0 +1,87 @@
|
||||
; *** Variables ***
|
||||
; Value of `SP` when basic was first invoked. This is where SP is going back to
|
||||
; on restarts.
|
||||
.equ BAS_INITSP BAS_RAMSTART
|
||||
; **Pointer** to current line number
|
||||
.equ BAS_PCURLN @+2
|
||||
.equ BAS_RAMEND @+2
|
||||
|
||||
; *** Code ***
|
||||
basStart:
|
||||
ld (BAS_INITSP), sp
|
||||
xor a
|
||||
ld hl, .welcome
|
||||
call printstr
|
||||
call printcrlf
|
||||
ld hl, .welcome+2 ; points to a zero word
|
||||
ld (BAS_PCURLN), hl
|
||||
jr basPrompt
|
||||
|
||||
.welcome:
|
||||
.db "OK", 0, 0
|
||||
|
||||
basPrompt:
|
||||
ld hl, .sPrompt
|
||||
call printstr
|
||||
call stdioReadLine
|
||||
call parseDecimal
|
||||
jr z, .number
|
||||
call basDirect
|
||||
jr basPrompt
|
||||
.number:
|
||||
; do nothing for now, we only support direct mode.
|
||||
ld hl, .sNumber
|
||||
call basPrintLn
|
||||
jr basPrompt
|
||||
.sNumber:
|
||||
.db "A number!", 0
|
||||
.sPrompt:
|
||||
.db "> ", 0
|
||||
|
||||
basDirect:
|
||||
ex de, hl
|
||||
ld hl, basCmds1
|
||||
.loop:
|
||||
ld a, 4
|
||||
call strncmp
|
||||
jr z, .found
|
||||
ld a, 6
|
||||
call addHL
|
||||
ld a, (hl)
|
||||
cp 0xff
|
||||
jr nz, .loop
|
||||
ld hl, .sUnknown
|
||||
jr basPrintLn
|
||||
|
||||
.found:
|
||||
inc hl \ inc hl \ inc hl \ inc hl
|
||||
call intoHL
|
||||
jp (hl)
|
||||
|
||||
.sUnknown:
|
||||
.db "Unknown command", 0
|
||||
|
||||
basPrintLn:
|
||||
call printcrlf
|
||||
call printstr
|
||||
jp printcrlf
|
||||
|
||||
; *** Commands ***
|
||||
basBYE:
|
||||
ld hl, .sBye
|
||||
call basPrintLn
|
||||
; To quit the loop, let's return the stack to its initial value and
|
||||
; then return.
|
||||
xor a
|
||||
ld sp, (BAS_INITSP)
|
||||
ret
|
||||
.sBye:
|
||||
.db "Goodbye!", 0
|
||||
|
||||
; direct only
|
||||
basCmds1:
|
||||
.db "bye", 0
|
||||
.dw basBYE
|
||||
; statements
|
||||
basCmds2:
|
||||
.db 0xff ; end of table
|
1
tools/emul/.gitignore
vendored
1
tools/emul/.gitignore
vendored
@ -4,4 +4,5 @@
|
||||
/*/*-bin.h
|
||||
/cfsin/zasm
|
||||
/cfsin/ed
|
||||
/cfsin/basic
|
||||
/cfsin/user.h
|
||||
|
@ -4,7 +4,7 @@ KERNEL = ../../kernel
|
||||
APPS = ../../apps
|
||||
ZASMBIN = zasm/zasm
|
||||
ZASMSH = ../zasm.sh
|
||||
SHELLAPPS = $(addprefix cfsin/, zasm ed)
|
||||
SHELLAPPS = $(addprefix cfsin/, zasm ed basic)
|
||||
CFSIN_CONTENTS = $(SHELLAPPS) cfsin/user.h
|
||||
|
||||
.PHONY: all
|
||||
|
Loading…
Reference in New Issue
Block a user