From 87fd6a1b9d284d80221c957d0eee1095165fa5af Mon Sep 17 00:00:00 2001
From: hugova <hugova@kth.se>
Date: Thu, 15 May 2025 17:05:28 +0200
Subject: [PATCH] make memset work more like c:s implementation.

---
 wip-hugo/STARTUP.s                     |  9 +++---
 wip-hugo/routines/line/line_test.s     |  6 ++--
 wip-hugo/routines/memory/mem.inc       |  3 +-
 wip-hugo/routines/memory/memcpy.s      |  7 -----
 wip-hugo/routines/memory/memcpy_test.s |  2 +-
 wip-hugo/routines/memory/memset.s      | 38 ++++++++++++--------------
 wip-hugo/routines/memory/memset_test.s |  9 ++++++
 wip-hugo/source.s                      |  5 ++--
 8 files changed, 37 insertions(+), 42 deletions(-)
 create mode 100644 wip-hugo/routines/memory/memset_test.s

diff --git a/wip-hugo/STARTUP.s b/wip-hugo/STARTUP.s
index 756e9c3..0067541 100755
--- a/wip-hugo/STARTUP.s
+++ b/wip-hugo/STARTUP.s
@@ -59,15 +59,14 @@
         STA Screen_RAM_settings
 
         ;; Paint the bitmap black. More bitmap: https://www.c64-wiki.com/wiki/53272, https://www.c64-wiki.com/wiki/Screen_RAM#Moving_of_screen_RAM
-        Mov_16 B_start, B_start + 1, #<VIC_bank, #>VIC_bank
-        Mov_16 B_end, B_end + 1, #<$5f3f,  #>$5f3f
+        Mov_16 A_start, A_start + 1, #<VIC_bank, #>VIC_bank
+        Mov_16 length, length + 1, #<$1f3f,  #>$1f3f
         LDA #$00
         jsr memset
 
-
         ;; Sets the screen color to black and white
-        Mov_16 B_start, B_start + 1, #<Screen_RAM, #>Screen_RAM
-        Mov_16 B_end, B_end + 1, #<Screen_RAM_end, #>Screen_RAM_end
+        Mov_16 A_start, A_start + 1, #<Screen_RAM, #>Screen_RAM
+        Mov_16 length, length + 1, #<$03E8, #>$03E8
         LDA #%11110000
         jsr memset
 
diff --git a/wip-hugo/routines/line/line_test.s b/wip-hugo/routines/line/line_test.s
index 0e67891..84876e9 100644
--- a/wip-hugo/routines/line/line_test.s
+++ b/wip-hugo/routines/line/line_test.s
@@ -50,10 +50,9 @@ end:
         ;;Long lines
         ;;Lets clear bitmap
         VIC_bank = $4000
-        VIC_bank_end = VIC_bank + $3FFF
         ;;Paint the bitmap black. More bitmap: https://www.c64-wiki.com/wiki/53272, https://www.c64-wiki.com/wiki/Screen_RAM#Moving_of_screen_RAM
-        Mov_16 B_start, B_start + 1, #<VIC_bank, #>VIC_bank
-        Mov_16 B_end, B_end + 1, #<$5f3f,  #>$5f3f
+        Mov_16 A_start, A_start + 1, #<VIC_bank, #>VIC_bank
+        Mov_16 length, length + 1, #<$1f40,  #>$1f40
         LDA #$00
         jsr memset
 
@@ -78,5 +77,4 @@ end:
         BEQ end_
         jmp @loop
 end_:
-        jmp exit
 .endscope
diff --git a/wip-hugo/routines/memory/mem.inc b/wip-hugo/routines/memory/mem.inc
index 5ee149f..c7ea9ac 100644
--- a/wip-hugo/routines/memory/mem.inc
+++ b/wip-hugo/routines/memory/mem.inc
@@ -3,5 +3,4 @@
         ;; public args
         A_start = $D0      ; 16-bit value (uses D1)
         B_start = $D2      ; 16-bit value (uses D3)
-        length = $D4        ; 16-bit value (uses D5)
-        B_end = length + 0
+        length = $D4        ; 16-bit value (uses D5), this is the number of bytes
diff --git a/wip-hugo/routines/memory/memcpy.s b/wip-hugo/routines/memory/memcpy.s
index de752f6..c99a1ae 100644
--- a/wip-hugo/routines/memory/memcpy.s
+++ b/wip-hugo/routines/memory/memcpy.s
@@ -16,13 +16,6 @@ change_length:
         DEC length +1
         BPL loop
         JMP loop_end
-
-        ;;;;check if length hi byte is 0. if it is end this
-        ;;LDA length + 1
-        ;;BEQ loop_end
-
-        ;;DEC length +1
-        ;;JMP loop
 y_overflow:
         LDY #$00
         INC B_start + 1
diff --git a/wip-hugo/routines/memory/memcpy_test.s b/wip-hugo/routines/memory/memcpy_test.s
index 9d2e5a8..a0845ed 100644
--- a/wip-hugo/routines/memory/memcpy_test.s
+++ b/wip-hugo/routines/memory/memcpy_test.s
@@ -1,6 +1,6 @@
 ;;; -*- Mode: asm; indent-tabs-mode: t; tab-width: 8 -*-
 ;; test for memcpy
-;; Writes text to half the screen
+;; Writes text to the screen
 .scope memcpy_test
         .include "mem.inc"
         VIC_bank = $4000
diff --git a/wip-hugo/routines/memory/memset.s b/wip-hugo/routines/memory/memset.s
index ea9d8cd..197bb02 100755
--- a/wip-hugo/routines/memory/memset.s
+++ b/wip-hugo/routines/memory/memset.s
@@ -4,28 +4,24 @@
 ;; Modifies A, X and B_start
 .proc memset
         .include "mem.inc"
-	;;put what to recursive write in Y.
-	LDX #$0
-	TAY
+        LDY #$00
 loop:
-	;;write to byte
-	TYA
-	STA (B_start ,X)
+        STA (A_start), Y
+        INY
+        BEQ y_overflow
+change_length:
+        DEC length
+        BNE loop
 
-	Add_16 B_start, B_start +1, #$01, #$00
+        DEC length +1
+        BPL loop
+        JMP loop_end
+y_overflow:
+        LDY #$00
+        INC B_start + 1
+        INC A_start + 1
 
-	LDA B_start
-	CMP B_end
-	BEQ test
-	jmp loop
-test:
-	LDA B_start +1
-	CMP B_end +1
-	BEQ end
-	jmp loop
-end:
-	;;Dont forget to rewrite last byte
-	TYA
-	STA (B_start, X)
-	RTS
+        jmp change_length
+loop_end:
+        RTS
 .endproc
diff --git a/wip-hugo/routines/memory/memset_test.s b/wip-hugo/routines/memory/memset_test.s
new file mode 100644
index 0000000..ff78baf
--- /dev/null
+++ b/wip-hugo/routines/memory/memset_test.s
@@ -0,0 +1,9 @@
+.scope memset_test
+        .include "mem.inc"
+        VIC_bank = $4000
+        len = $1f40
+        Mov_16 A_start, A_start + 1, #<VIC_bank, #>VIC_bank
+        Mov_16 length,  length  + 1, #<len, #>len
+        LDA #%01010101
+        JSR memset
+.endscope
diff --git a/wip-hugo/source.s b/wip-hugo/source.s
index 66e0ec6..aaf40c6 100755
--- a/wip-hugo/source.s
+++ b/wip-hugo/source.s
@@ -8,10 +8,11 @@
 .include "STARTUP.s"
 ;.include "dubbel_buffer/raster_irqs.s"
 
-;.include "routines/line/line_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/memcpy_test.s"
+.include "routines/memory/memset_test.s"
 ;.include "routines/triangle/triangle_test.s"
 exit:
 JMP exit