optimise memset_alt.s

wip-hugo/routines/memory/mem.inc

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

wip-hugo/routines/memory/memset_alt.s

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

wip-hugo/source.s

@@ -28,7 +28,7 @@ JMP exit
 .include "routines/pixel/pixel_draw.s"
 .include "routines/pixel/pixel_calc.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/arithmatic/mult.s"
 .include "routines/arithmatic/div.s"