add general multiplication implementation

wip-hugo/routines/arithmatic/arithmatic.inc

@@ -0,0 +1,4 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
+;; public args
+VAL_A = ARGVEC + 0
+VAL_B = ARGVEC + 1

wip-hugo/routines/arithmatic/mult.s

@@ -0,0 +1,27 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
+        ;;I thoughtout russan thing
+        ;;X * %1111001
+        ;;= X + X*%1111000
+        ;;= X + X*%1000  *%11111
+        ;; to remember this for later, for duuqnds papper
+
+.proc mult; user-procedure :clobbers A :clobbers-arguments 2
+
+        ;; https://en.wikipedia.org/wiki/Ancient_Egyptian_multiplication#Russian_peasant_multiplication
+
+        .include "arithmatic.inc"
+
+        LDA #$00
+loop:
+        ASL VAL_B
+        ROR VAL_A; add to awnser if VAL_A is odd
+        BCC loop
+
+        LSR VAL_B
+        ADC VAL_B; add val_b because val_a was odd.
+        ASL VAL_B
+
+        BNE loop
+endloop:
+        RTS
+.endproc

wip-hugo/routines/arithmatic/mult_test.s

@@ -0,0 +1,10 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
+;;Calculates $11 * $0E = $EE
+.scope mult_test
+        .include "arithmatic.inc"
+        LDA #$0F
+        STA VAL_A
+        LDA #$07
+        STA VAL_B
+        JSR mult; A = $69 if it works as it should
+.endscope

wip-hugo/routines/pixel/pixel_test.s

@@ -1,3 +1,4 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
 .scope pixel_test
         .include "pixel.inc"
         LDA #$40

wip-hugo/routines/text/char.inc

@@ -1,4 +1,5 @@
-       ;; public args
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
+        ;; public args
        X_pos   = ARGVEC + 0
        Y_pos   = ARGVEC + 1
        code    = ARGVEC + 2

wip-hugo/routines/text/char_draw_test.s

@@ -1,3 +1,4 @@
+;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
 .scope char_draw_test
         .include "char.inc"
         LDA #$10

wip-hugo/source.s

@@ -8,11 +8,12 @@
 .include "STARTUP.s"
 ;.include "dubbel_buffer/raster_irqs.s"
 
+.include "routines/arithmatic/mult_test.s"
 ;.include "routines/line/line_test.s"
 ;.include "routines/text/char_draw_test.s"
 ;.include "routines/pixel/pixel_test.s"
 ;.include "routines/memory/memcpy_test.s"
-.include "routines/memory/memset_test.s"
+;.include "routines/memory/memset_test.s"
 ;.include "routines/triangle/triangle_test.s"
 exit:
 JMP exit
@@ -23,4 +24,5 @@ JMP exit
 .include "routines/text/char_draw.s"
 .include "routines/memory/memset.s"
 .include "routines/memory/memcpy.s"
+.include "routines/arithmatic/mult.s"
 .include "END.s"