From a0dbd2d509bd412af1441d3874f64501a0943047 Mon Sep 17 00:00:00 2001
From: Lizzy Fleckenstein <lizzy@vlhl.dev>
Date: Sun, 10 Dec 2023 16:57:58 +0100
Subject: replace memory.asm with C

---
 stage3/memory.asm | 59 -------------------------------------------------------
 stage3/memory.c   | 42 +++++++++++++++++++++++++++++++++++++++
 stage3/memory.h   |  9 +++++----
 stage3/memory2.c  | 22 ---------------------
 4 files changed, 47 insertions(+), 85 deletions(-)
 delete mode 100644 stage3/memory.asm
 create mode 100644 stage3/memory.c
 delete mode 100644 stage3/memory2.c

(limited to 'stage3')

diff --git a/stage3/memory.asm b/stage3/memory.asm
deleted file mode 100644
index b4410a3..0000000
--- a/stage3/memory.asm
+++ /dev/null
@@ -1,59 +0,0 @@
-global memcpy, memmove
-
-section .text
-
-memcpy:
-.bulk_copy:
-	cmp rdx, 8
-	jl .bytewise_copy
-	mov rax, qword[rsi]
-	mov qword[rdi], rax
-	sub rdx, 8
-	add rdi, 8
-	add rsi, 8
-.bytewise_copy:
-	cmp rdx, 0
-	je .return
-	mov al, byte[rsi]
-	mov byte[rdi], al
-	dec rdx
-	inc rdi
-	inc rsi
-	jmp .bytewise_copy
-.return:
-	ret
-
-memmove:
-	mov rcx, rdx
-.bulk_read:
-	cmp rdx, 8
-	jl .bytewise_read
-	push qword[rsi]
-	add rsi, 8
-	sub rdx, 8
-	jmp .bulk_read
-.bytewise_read:
-	cmp rdx, 0
-	je .bulk_write
-	dec rsp
-	mov al, byte[rsi]
-	mov byte[rsp], al
-	inc rsi
-	dec rdx
-	jmp .bytewise_read
-.bulk_write:
-	cmp rcx, 8
-	jl .bytewise_write
-	pop qword[rdi]
-	add rdi, 8
-	sub rcx, 8
-.bytewise_write:
-	cmp rcx, 0
-	je .return
-	mov al, byte[rsp]
-	mov byte[rdi], al
-	inc rsp
-	inc rdi
-	dec rcx
-.return:
-	ret
diff --git a/stage3/memory.c b/stage3/memory.c
new file mode 100644
index 0000000..fcf5a28
--- /dev/null
+++ b/stage3/memory.c
@@ -0,0 +1,42 @@
+#include "heap.h"
+#include "memory.h"
+
+void *memcpy(void *dst, const void *src, usize bytes)
+{
+	for (usize i = 0; i < bytes; i++)
+		((unsigned char *) dst)[i] = ((const unsigned char *) src)[i];
+}
+
+int memcpy_r(void *dst, const void *src, usize bytes)
+{
+	for (usize i = bytes; i > 0; i--)
+		((unsigned char *) dst)[i-1] = ((const unsigned char *) src)[i-1];
+}
+
+int memcmp(const void *s1, const void *s2, usize n)
+{
+	for (usize i = 0; i < n; i++) {
+		unsigned char c1 = ((const unsigned char *) s1)[i];
+		unsigned char c2 = ((const unsigned char *) s2)[i];
+
+		if (c1 != c2)
+			return (int) c1 - (int) c2;
+	}
+
+	return 0;
+}
+
+u8 memsum(const void *ptr, usize size)
+{
+	u8 sum = 0;
+	for (usize i = 0; i < size; i++)
+		sum += ((const u8 *) ptr)[i];
+	return sum;
+}
+
+void *memset(void *ptr, int value, usize size)
+{
+	for (usize i = 0; i < size; i++)
+		((unsigned char *) ptr)[i] = value;
+	return ptr;
+}
diff --git a/stage3/memory.h b/stage3/memory.h
index 774d596..56de49d 100644
--- a/stage3/memory.h
+++ b/stage3/memory.h
@@ -3,9 +3,10 @@
 
 #include "def.h"
 
-void memcpy(void *dst, const void *src, usize bytes); // memory.asm
-void memmove(void *dst, const void *src, usize bytes); // memory.asm
-int memcmp(const void *s1, const void *s2, usize n); // memory2.c
-u8 memsum(const void *ptr, usize size); // memory2.c
+void *memcpy(void *dst, const void *src, usize bytes);
+int memcpy_r(void *dst, const void *src, usize bytes);
+int memcmp(const void *s1, const void *s2, usize n);
+u8 memsum(const void *ptr, usize size);
+void *memset(void *s, int c, usize n);
 
 #endif
diff --git a/stage3/memory2.c b/stage3/memory2.c
deleted file mode 100644
index cca3cb1..0000000
--- a/stage3/memory2.c
+++ /dev/null
@@ -1,22 +0,0 @@
-#include "memory.h"
-
-int memcmp(const void *s1, const void *s2, usize n)
-{
-	for (usize i = 0; i < n; i++) {
-		unsigned char c1 = ((const unsigned char *) s1)[i];
-		unsigned char c2 = ((const unsigned char *) s2)[i];
-
-		if (c1 != c2)
-			return (int) c1 - (int) c2;
-	}
-
-	return 0;
-}
-
-u8 memsum(const void *ptr, usize size)
-{
-	u8 sum = 0;
-	for (usize i = 0; i < size; i++)
-		sum += ((const u8 *) ptr)[i];
-	return sum;
-}
-- 
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