Stacken/c64-livecoding
6
0
Fork 0
Code Issues 1 Pull requests Projects Releases Packages Wiki Activity Actions

optimise memset_alt.s

Browse source
This commit is contained in:
hugova 2025-07-16 18:52:35 +02:00
parent bf7021a3a9
commit 38070296d0
3 changed files with 18 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
wip-hugo/routines/memory/mem.inc
View file

@ -9,3 +9,4 @@
data_to_write = $D8 data_to_write = $D8
length_copy = $d9 ; 16-bit vale (uses da) length_copy = $d9 ; 16-bit vale (uses da)
instruction_backup = $db instruction_backup = $db
Y_copy =$dc

28
wip-hugo/routines/memory/memset_alt.s
View file

@ -32,25 +32,29 @@ small_set:
STA length_copy STA length_copy
;; calculate rts-position ;; calculate rts-position
LDA #$00 LDX #$00
STA length + 1 STX length + 1
;; 4 bytes = STA DEY NOP = seting 1 byte of memory. ;; 3 bytes = STA DEY NOP = seting 1 byte of memory.
;; So we need to calculate: length*4 ;; So we need to calculate: length*3
Mult_16 length, length + 1 Mult_16 length, length + 1
Add_16 length, length + 1, length_copy, #$00 ; A= length_copy
;; Now RTS_pointer = length*4 + big_set_label
CLC
LDA #<big_set
ADC length ADC length
TAY
LDA length + 1
ADC #$00
STA length + 1
;; Now RTS_pointer + Y = length*3 + big_set_label
LDA #<big_set
STA RTS_pointer STA RTS_pointer
LDA #>big_set LDA #>big_set
ADC length + 1 ADC length + 1
STA RTS_pointer + 1 STA RTS_pointer + 1
;; read data we will change to RTS ;; read data we will change to RTS
LDY #$00 STY Y_copy
LDA (RTS_pointer), Y LDA (RTS_pointer), Y
STA instruction_backup TAX
;; set RTS in big_set ;; set RTS in big_set
LDA #$60 LDA #$60
@ -63,8 +67,8 @@ small_set:
JSR big_set JSR big_set
;; revert changes ;; revert changes
LDY #$00 LDY Y_copy
LDA instruction_backup TXA
STA (RTS_pointer), Y STA (RTS_pointer), Y
RTS RTS

2
wip-hugo/source.s
View file

@ -28,7 +28,7 @@ JMP exit
.include "routines/pixel/pixel_draw.s" .include "routines/pixel/pixel_draw.s"
.include "routines/pixel/pixel_calc.s" .include "routines/pixel/pixel_calc.s"
.include "routines/text/char_draw.s" .include "routines/text/char_draw.s"
.include "routines/memory/memset.s" .include "routines/memory/memset_alt.s"
.include "routines/memory/memcpy.s" .include "routines/memory/memcpy.s"
.include "routines/arithmatic/mult.s" .include "routines/arithmatic/mult.s"
.include "routines/arithmatic/div.s" .include "routines/arithmatic/div.s"