neilrhalliday / gbpextension

STOS Basic GBP Extension

The GBP Extension for STOS Basic by GBP

The GBP Extension introduces a number of additional commands to the STOS Basic language for the Atari ST. Here you can find the full source code for the interpreter and the compiler version of the extension, along with a number of STOS basic example files for using the commands. See MANUAL.TXT for full instructions on how the new commands work.

Enjoy!

Neil Halliday, August 2021

gbpextension's Issues

Absolute addresses used in compiler extension

There are some places that will generate absolute addresses. As you certainly know, that does not work in compiler extensions:

GBPExtension/GBPFULL.EXT/COMPILER.S

Line 349 in a5ff622

lea .place,a0

GBPExtension/GBPFULL.EXT/COMPILER.S

Line 620 in a5ff622

move.l a1,(addr) ; save dest addr

GBPExtension/GBPFULL.EXT/COMPILER.S

Line 697 in a5ff622

move.l (addr),a2

GBPExtension/GBPFULL.EXT/COMPILER.S

Lines 1393 to 1423 in a5ff622

	move.w d0,playmode
	move.w d1,stereo
	move.b d2,espeed
	move.l a0,samlength
	move.l a1,samstart
	move.w stereo,d0
	mulu #$80,d0 ; Normalize stereo/mono mode
	move.w d0,stereo
	move.w #0,d0 ; Combine frequency and mode
	move.b espeed,d0 ; Save frequency
	move.w stereo,d1 ; Save mono/stereo $80 = mono
	or.w d1,d0 ; Combine data
	move.w d0,$ff8920 ; Store in DAC MODE address
	move.l samstart,d0 ; Store start address
	move.l samstart,d1
	add.l samlength,d1 ; Create end address
	move.l #$ff8902,a2 ; Get frame start HIGH byte
	movep.w d0,3(a2) ; Store mid & low bytes
	swap d0 ; Reverse data
	move.b d0,1(a2) ; Store high byte
	move.l #$ff890e,a2 ; Get frame end HIGH byte
	movep.w d1,3(a2) ; Store mid & low bytes
	swap d1 ; Reverse data
	move.b d1,1(a2) ; Store high byte
	move.w playmode,$ff8900 ; Start/stop sample

Missing '#''?

The line

GBPExtension/GBPFULL.EXT/INTERPRE.S

Line 151 in a5ff622

move.b $40,$ff8802 ; Send info to sound chip

accesses the absolute address $40. I think there is a missing '#' ;)