From 9a06f770c23c72e7b0299a9f91c4831f90d1e9ea Mon Sep 17 00:00:00 2001
From: hugova <hugova@kth.se>
Date: Fri, 16 May 2025 10:40:55 +0200
Subject: [PATCH] add general multiplication implementation

---
 wip-hugo/routines/arithmatic/arithmatic.inc |  4 +++
 wip-hugo/routines/arithmatic/mult.s         | 27 +++++++++++++++++++++
 wip-hugo/routines/arithmatic/mult_test.s    | 10 ++++++++
 wip-hugo/routines/pixel/pixel_test.s        |  1 +
 wip-hugo/routines/text/char.inc             |  3 ++-
 wip-hugo/routines/text/char_draw_test.s     |  1 +
 wip-hugo/source.s                           |  4 ++-
 7 files changed, 48 insertions(+), 2 deletions(-)
 create mode 100644 wip-hugo/routines/arithmatic/arithmatic.inc
 create mode 100644 wip-hugo/routines/arithmatic/mult.s
 create mode 100644 wip-hugo/routines/arithmatic/mult_test.s

diff --git a/wip-hugo/routines/arithmatic/arithmatic.inc b/wip-hugo/routines/arithmatic/arithmatic.inc
new file mode 100644
index 0000000..02ebd5a
--- /dev/null
+++ b/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
diff --git a/wip-hugo/routines/arithmatic/mult.s b/wip-hugo/routines/arithmatic/mult.s
new file mode 100644
index 0000000..b0c7056
--- /dev/null
+++ b/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
diff --git a/wip-hugo/routines/arithmatic/mult_test.s b/wip-hugo/routines/arithmatic/mult_test.s
new file mode 100644
index 0000000..2095ef2
--- /dev/null
+++ b/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
diff --git a/wip-hugo/routines/pixel/pixel_test.s b/wip-hugo/routines/pixel/pixel_test.s
index 2839703..164a634 100644
--- a/wip-hugo/routines/pixel/pixel_test.s
+++ b/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
diff --git a/wip-hugo/routines/text/char.inc b/wip-hugo/routines/text/char.inc
index 5f80983..ea4b70a 100644
--- a/wip-hugo/routines/text/char.inc
+++ b/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
diff --git a/wip-hugo/routines/text/char_draw_test.s b/wip-hugo/routines/text/char_draw_test.s
index 2a54446..63d5361 100644
--- a/wip-hugo/routines/text/char_draw_test.s
+++ b/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
diff --git a/wip-hugo/source.s b/wip-hugo/source.s
index 70912de..7f640b6 100755
--- a/wip-hugo/source.s
+++ b/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"