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mockingboard: add a detect routine

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not tested
This commit is contained in:
Vince Weaver 2018-02-05 13:28:44 -05:00
parent b10bf70781
commit 2901c748d7
2 changed files with 62 additions and 3 deletions
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49
asm_routines/mockingboard.s
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@ -151,3 +151,52 @@ clear_ay_right_loop:
rts
;=======================================
; Detect a Mockingboard card
;=======================================
; Based on code from the French Touch "Pure Noise" Demo
; Attempts to time an instruction sequence with a 6522
;
; If found, puts in bMB
; OUT2: has address of Mockingboard
bMB EQU $03
OUT2 EQU $22 ; +$21
bGood EQU $FE ; 0 : ok / 1 : bad
Temp EQU $FF ;
mockingboard_detect:
lda #0
sta OUT2
mb_detect_loop: ; self-modifying
lda #$07 ; we start in slot 7 ($C7) and go down to 0 ($C0)
ora #$C0 ; make it start with C
sta OUT2+1
ldy #04 ; $CX04
ldx #02 ; 2 tries?
mb_check_cycle_loop:
lda (OUT2),Y ; timer 6522 (Low Order Counter)
; count down
sta Temp ; 3 cycles
lda (OUT2),Y ; + 5 cycles = 8 cycles
; between the two accesses to the timer
sec
sbc Temp ; subtract to see if we had 8 cycles
cmp #$f8 ; -8
bne mb_not_in_this_slot
dex ; decrement, try one more time
bne mb_check_cycle_loop ; loop detection
inx ; Mockingboard found (X=1)
done_mb_detect:
stx bMB ; store result to bMB
rts ; return
mb_not_in_this_slot:
dec mb_detect_loop+1 ; decrement the "slot" (self_modify)
bne mb_detect_loop ; loop down to one
inc bGood ; didn't find?
ldx #00
beq done_mb_detect

16
ksp/applesoft/Makefile
View File

@ -5,7 +5,17 @@ SHAPETABLE = ../../hgr-utils/shape_table
all: ksp.dsk
ACMPLX.BAS: acmplx.bas
$(TXT2BAS):
cd ../../asoft_basic-utils && make
$(SHAPETABLE):
cd ../../hgr-utils && make
$(PCX2HGR):
cd ../../hgr-utils && make
ACMPLX.BAS: acmplx.bas $(TXT2BAS)
$(TXT2BAS) < acmplx.bas > ACMPLX.BAS
CONTRACT.BAS: contract.bas
@ -32,10 +42,10 @@ VAB.BAS: vab.bas
LOAD_KSP.BAS: load_ksp.bas
$(TXT2BAS) < load_ksp.bas > LOAD_KSP.BAS
ROCKET.SHAPE: ../ship2.table
ROCKET.SHAPE: ../ship2.table $(SHAPETABLE)
$(SHAPETABLE) -b < ../ship2.table > ROCKET.SHAPE
VAB.SHAPE: ../ship.table
VAB.SHAPE: ../ship.table $(SHAPETABLE)
$(SHAPETABLE) -b < ../ship.table > VAB.SHAPE