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fire: shave off a byte thanks to qkumba

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This commit is contained in:
Vince Weaver
2019-01-02 22:40:06 -05:00
parent 9e11243d24
commit 10b502564a
2 changed files with 15 additions and 5 deletions
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12
fire/fire_firmware.s
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@@ -34,7 +34,8 @@
; 106 bytes -- assume bit 8 is as random as bit 0 ; 106 bytes -- assume bit 8 is as random as bit 0
; 82 bytes -- use VTAB in firmware to setup addresses ; 82 bytes -- use VTAB in firmware to setup addresses
; (Antoine Vignau on comp.sys.apple2 reminded me of this) ; (Antoine Vignau on comp.sys.apple2 reminded me of this)
; 81 bytes -- qkumba points out that GR leaves BASL:BASH pointing at line 23
; so we can use Y-indirect of BASL to draw the bottom white line
; Zero Page ; Zero Page
SEEDL = $4E SEEDL = $4E
@@ -82,16 +83,19 @@ fire_demo:
; Setup white line on bottom ; Setup white line on bottom
; note: calling HLINE in firmware would take at least 13 bytes ; note: calling HLINE in firmware would take at least 13 bytes
; open coded is 10
; below code is 9
; we depend on the call to MON_SETGR leaving BASL:BASH set for line 39
; (thanks to qkumba)
lda #$ff ; 2 lda #$ff ; 2
ldy #39 ; 2 ldy #39 ; 2
white_loop: white_loop:
sta $7d0,Y ; hline 24 (46+47) ; 3 sta (BASL),Y ; hline 23 (46+47) ; 2
dey ; 1 dey ; 1
bpl white_loop ; 2 bpl white_loop ; 2
;============ ;============
; 10 ; 9
fire_loop: fire_loop:

8
fire/fire_tiny.s
View File

@@ -32,6 +32,9 @@
; 109 bytes -- replace BIT/OR in low calc with an ADC ; 109 bytes -- replace BIT/OR in low calc with an ADC
; 107 bytes -- replace self-modifying load/store absolute with Y-indirect ; 107 bytes -- replace self-modifying load/store absolute with Y-indirect
; 106 bytes -- assume bit 8 is as random as bit 0 ; 106 bytes -- assume bit 8 is as random as bit 0
; 105 bytes -- qkumba points out that GR leaves BASL:BASH pointing at line 23
; so we can use Y-indirect of BASL to draw the bottom white line
; Zero Page ; Zero Page
SEEDL = $4E SEEDL = $4E
@@ -41,6 +44,7 @@ OUTL = $02
OUTH = $03 OUTH = $03
INL = $04 INL = $04
INH = $05 INH = $05
BASL = $28
; 100 = $64 ; 100 = $64
@@ -64,10 +68,12 @@ fire_demo:
; Setup white line on bottom ; Setup white line on bottom
; GR leaves BASL pointing at hline 23
lda #$ff ; 2 lda #$ff ; 2
ldy #39 ; 2 ldy #39 ; 2
white_loop: white_loop:
sta $7d0,Y ; hline 24 (46+47) ; 3 sta (BASL),Y ; hline 23 (46+47) ; 3
dey ; 1 dey ; 1
bpl white_loop ; 2 bpl white_loop ; 2
;============ ;============