From 97b83208bbd07c59c8576b690828f60d11b7ccd9 Mon Sep 17 00:00:00 2001
From: nub31 <oliverlhs@outlook.com>
Date: Thu, 26 Jun 2025 13:30:22 +0200
Subject: [PATCH] ...

---
 src/runtime/.gitignore        |  2 +-
 src/runtime/makefile          |  4 +--
 src/runtime/platform/x86_64.s | 17 +++++++++++++
 src/runtime/runtime.c         | 48 ++++++++++++++++++++---------------
 4 files changed, 47 insertions(+), 24 deletions(-)
 create mode 100644 src/runtime/platform/x86_64.s

diff --git a/src/runtime/.gitignore b/src/runtime/.gitignore
index 7a49c57..1530978 100644
--- a/src/runtime/.gitignore
+++ b/src/runtime/.gitignore
@@ -1 +1 @@
-runtime.o
\ No newline at end of file
+*.o
\ No newline at end of file
diff --git a/src/runtime/makefile b/src/runtime/makefile
index 00fdd78..c0aed79 100644
--- a/src/runtime/makefile
+++ b/src/runtime/makefile
@@ -1,5 +1,5 @@
-runtime:
-	cc -c runtime.c
+x86_64:
+	gcc -nostdlib -ffreestanding -c platform/x86_64.s runtime.c
 
 clean:
 	rm runtime.o
diff --git a/src/runtime/platform/x86_64.s b/src/runtime/platform/x86_64.s
new file mode 100644
index 0000000..78ef7ad
--- /dev/null
+++ b/src/runtime/platform/x86_64.s
@@ -0,0 +1,17 @@
+.intel_syntax noprefix
+
+.text
+.globl nub_write_string
+# void nub_write_string(const char* str)
+nub_write_string:
+    mov rsi, rdi
+    mov rdi, 1
+    mov rax, 1
+    syscall
+
+.text
+.globl nub_exit
+# void nub_exit(int code)
+nub_exit:
+    mov rax, 60
+    syscall
diff --git a/src/runtime/runtime.c b/src/runtime/runtime.c
index 1173ff4..a9b8729 100644
--- a/src/runtime/runtime.c
+++ b/src/runtime/runtime.c
@@ -1,16 +1,17 @@
 #include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/syscall.h>
-#include <syscall.h>
-#include <unistd.h>
 
 #define NUB_PANIC_ERROR_CODE 101
 
-uint64_t nub_cstring_length(char* string)
+extern void nub_write_string(const char* str);
+extern void nub_exit(int code);
+
+uint64_t nub_cstring_length(const char* string)
 {
-    return strlen(string);
+    uint64_t len = 0;
+    while (string[len] != '\0') {
+        len++;
+    }
+    return len;
 }
 
 uint64_t nub_string_length()
@@ -18,32 +19,37 @@ uint64_t nub_string_length()
     return 0;
 }
 
-void nub_memcpy(void* source, void* destination, uint64_t length)
+void nub_memcpy(uint8_t* source, uint8_t* destination, uint64_t length)
 {
-    memcpy(destination, source, length);
+    for (uint64_t i = 0; i < length; i++) {
+        destination[i] = source[i];
+    }
 }
 
-void nub_memset(void* destination, int value, uint64_t count)
+void nub_memset(uint8_t* destination, uint8_t value, uint64_t count)
 {
-    memset(destination, value, count);
+    for (uint64_t i = 0; i < count; i++) {
+        destination[i] = value;
+    }
 }
 
 void nub_panic_array_oob()
 {
-    puts("Array out of bounds");
-    exit(NUB_PANIC_ERROR_CODE);
+    nub_write_string("Array out of bounds\n");
+    nub_exit(NUB_PANIC_ERROR_CODE);
 }
 
 void nub_panic_oom()
 {
-    puts("Out of memory");
-    exit(NUB_PANIC_ERROR_CODE);
+    nub_write_string("Out of memory\n");
+    nub_exit(NUB_PANIC_ERROR_CODE);
 }
 
-extern int64_t main();
+extern int main();
 
-void _start()
+__attribute__((noreturn)) void _start()
 {
-    int64_t exit_code = main();
-    exit(exit_code);
-}
\ No newline at end of file
+    int exit_code = main();
+    nub_exit(exit_code);
+    __builtin_unreachable();
+}