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Creativison changes. 

This change includes some cleanups, removal of mainargs.s (game console
programs never have arguments), and a workaround for a problem I'm seeing.

The problem is that sometimes (in fact, more often than not) the clrscr()
call in testcode/lib/joy-test.c writes some garbage chars on the screen (most
often a "P"). Could be my hardware (I haven't seen it on MAME), but to
me the root cause is still unknown.
This commit is contained in:
Christian Groessler 2017-03-17 21:42:51 +01:00
parent 0bbe4f56a5
commit a3d8829be9
6 changed files with 21 additions and 37 deletions
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7
asminc/creativision.inc
View File

@ -10,10 +10,10 @@ CURSOR_X = $3C
CURSOR_Y = $3D
;** VDP
VDP_CONTROL_W = $3001
VDP_DATA_W = $3000
VDP_STATUS_R = $2001
VDP_DATA_R = $2000
VDP_STATUS_R = $2001
VDP_DATA_W = $3000
VDP_CONTROL_W = $3001
;** PIA
PIA0_DATA = $1000
@ -58,3 +58,4 @@ JOY_NNW = $4A
BIOS_IRQ1_ADDR = $FF3F
BIOS_IRQ2_ADDR = $FF52
BIOS_NMI_RESET_ADDR = $F808
BIOS_WRITE_VDP_REG = $FE1F

2
cfg/creativision.cfg
View File

@ -4,7 +4,7 @@ SYMBOLS {
MEMORY {
ZP: file = "", define = yes, start = $0020, size = $00E0;
RAM: file = "", define = yes, start = $01FA, size = $0206;
ROM: file = %O, define = yes, start = $B000, size = $1000;
ROM: file = %O, define = yes, start = $B000, size = $1000, fill = yes, fillval = $FF;
}
SEGMENTS {
ZEROPAGE: load = ZP, type = zp;

6
libsrc/creativision/clrscr.s
View File

@ -18,7 +18,7 @@ _clrscr:
lda #$50 ; VRAM offset high ($10 OR $40)
sta VDP_CONTROL_W
lda #$C0 ; Space from ROM setup
lda #$40 ; Space char from ROM setup
ldx #0
ldy #3
@ -34,8 +34,8 @@ L1: sta VDP_DATA_W
lda #0
sta CURSOR_X
sta CURSOR_Y
sta <SCREEN_PTR
sta SCREEN_PTR
lda #$10
sta >SCREEN_PTR
sta SCREEN_PTR+1
rts

6
libsrc/creativision/cputc.s
View File

@ -96,8 +96,8 @@ BAD_CHAR:
jmp plot
;-----------------------------------------------------------------------------
; Initialize the conio subsystem. Code goes into the INIT segment, which may
; be reused after startup.
; Initialize the conio subsystem. "INIT" segment is nothing special on the
; Creativision, it is part of the "ROM" memory.
.segment "INIT"
@ -122,4 +122,4 @@ LL: lda boxchars,x
bne LL
cli
jmp plot
jmp plot

15
libsrc/creativision/crt0.s
View File

@ -31,9 +31,6 @@ entry:
ldx #<__RAM_START__ - 1
txs
; Start interrupts
cli
; Clear the BSS data
jsr zerobss
@ -49,13 +46,21 @@ entry:
; Call module constructors
jsr initlib
; enable vertical blank interrupts in the display controller
lda #$E0 ; 16K RAM, Active Display, Mode 1, VBI enabled
ldx #$01 ; Register 1
jsr BIOS_WRITE_VDP_REG
; Start interrupts
cli
; Call main()
jsr callmain
; Call module destructors. This is also the _exit entry.
_exit: jsr donelib
; TODO: Replace with some sort of reset
; A Creativision program isn't supposed to exit.
loop: jmp loop
; ------------------------------------------------------------------------
@ -81,7 +86,7 @@ irq2: jmp BIOS_IRQ2_ADDR
; VDP Setup
; This sets to Graphics Mode 1
.byte $00 ; Register 0
.byte $E0 ; Register 1 16K RAM, Active Display, Mode 1, VBI enabled
.byte $C0 ; Register 1 16K RAM, Active Display, Mode 1, VBI disabled
.byte $04 ; Register 2 Name Table at $1000 - $12FF
.byte $60 ; Register 3 Colour Table at $1800 - $181F
.byte $00 ; Register 4 Pattern Table at $0000 - $07FF

22
libsrc/creativision/mainargs.s
View File

@ -1,22 +0,0 @@
;
; Ullrich von Bassewitz, 2003-03-07
;
; Setup arguments for main
;
.constructor initmainargs, 24
.import __argc, __argv
;---------------------------------------------------------------------------
; Get possible command-line arguments. Goes into the special INIT segment,
; which may be reused after the startup code is run
.segment "INIT"
.proc initmainargs
rts
.endproc