From a0672be24d53ec78d1a2567cf60d9f774b0d158a Mon Sep 17 00:00:00 2001
From: Xavier Del Campo Romero <xavi92@disroot.org>
Date: Fri, 4 Jul 2025 02:54:54 +0200
Subject: Do not rely on PSXSDK libc or _start

---
 src/libc/CMakeLists.txt   |  8 ++++++++
 src/libc/include/stddef.h |  8 ++++++++
 src/libc/include/stdlib.h |  7 +++++++
 src/libc/include/string.h | 12 ++++++++++++
 src/libc/src/memcmp.c     | 12 ++++++++++++
 src/libc/src/memcpy.c     | 13 +++++++++++++
 src/libc/src/memset.c     |  7 +++++++
 src/libc/src/strchr.c     | 11 +++++++++++
 src/libc/src/strlen.c     | 12 ++++++++++++
 9 files changed, 90 insertions(+)
 create mode 100644 src/libc/CMakeLists.txt
 create mode 100644 src/libc/include/stddef.h
 create mode 100644 src/libc/include/stdlib.h
 create mode 100644 src/libc/include/string.h
 create mode 100644 src/libc/src/memcmp.c
 create mode 100644 src/libc/src/memcpy.c
 create mode 100644 src/libc/src/memset.c
 create mode 100644 src/libc/src/strchr.c
 create mode 100644 src/libc/src/strlen.c

(limited to 'src/libc')

diff --git a/src/libc/CMakeLists.txt b/src/libc/CMakeLists.txt
new file mode 100644
index 0000000..b9bb597
--- /dev/null
+++ b/src/libc/CMakeLists.txt
@@ -0,0 +1,8 @@
+set(inc "include")
+set(src
+"src/memcpy.c"
+"src/memset.c"
+"src/strlen.c"
+)
+add_library(c ${src})
+target_include_directories(c PUBLIC ${inc})
diff --git a/src/libc/include/stddef.h b/src/libc/include/stddef.h
new file mode 100644
index 0000000..123e46f
--- /dev/null
+++ b/src/libc/include/stddef.h
@@ -0,0 +1,8 @@
+#ifndef _STDDEF_H
+#define _STDDEF_H
+
+#define NULL ((void *)0)
+
+typedef unsigned long size_t;
+
+#endif
diff --git a/src/libc/include/stdlib.h b/src/libc/include/stdlib.h
new file mode 100644
index 0000000..79d3122
--- /dev/null
+++ b/src/libc/include/stdlib.h
@@ -0,0 +1,7 @@
+#ifndef _STDLIB_H
+#define _STDLIB_H
+
+#define EXIT_SUCCESS 0
+#define EXIT_FAILURE 1
+
+#endif
diff --git a/src/libc/include/string.h b/src/libc/include/string.h
new file mode 100644
index 0000000..7efda4e
--- /dev/null
+++ b/src/libc/include/string.h
@@ -0,0 +1,12 @@
+#ifndef _STRING_H
+#define _STRING_H
+
+#include <stddef.h>
+
+int memcmp(const void *__s1, const void *__s2, size_t __n);
+void *memcpy(void *__dst, const void *__src, size_t __n);
+void *memset(void *__dst, int __c, size_t __n);
+char *strchr(const char *__s, int __n);
+size_t strlen(const char *__s);
+
+#endif
diff --git a/src/libc/src/memcmp.c b/src/libc/src/memcmp.c
new file mode 100644
index 0000000..f24d300
--- /dev/null
+++ b/src/libc/src/memcmp.c
@@ -0,0 +1,12 @@
+#include <string.h>
+
+int memcmp(const void *const s1, const void *const s2, const size_t n)
+{
+    const unsigned char *a = s1, *b = s2;
+
+    for (size_t i = 0; i < n; i++, a++, b++)
+        if (*a != *b)
+            return *a - *b;
+
+    return 0;
+}
diff --git a/src/libc/src/memcpy.c b/src/libc/src/memcpy.c
new file mode 100644
index 0000000..7014e63
--- /dev/null
+++ b/src/libc/src/memcpy.c
@@ -0,0 +1,13 @@
+#include <string.h>
+#include <stddef.h>
+
+void *memcpy(void *const dst, const void *const src, const size_t n)
+{
+    unsigned char *d = dst;
+    const unsigned char *s = src;
+
+    for (size_t i = 0; i < n; i++)
+        *d++ = *s++;
+
+    return dst;
+}
diff --git a/src/libc/src/memset.c b/src/libc/src/memset.c
new file mode 100644
index 0000000..d3f00c1
--- /dev/null
+++ b/src/libc/src/memset.c
@@ -0,0 +1,7 @@
+#include <string.h>
+#include <stddef.h>
+
+void *memset(void *const dst, const int c, const size_t n)
+{
+    return NULL;
+}
diff --git a/src/libc/src/strchr.c b/src/libc/src/strchr.c
new file mode 100644
index 0000000..3a1fd0b
--- /dev/null
+++ b/src/libc/src/strchr.c
@@ -0,0 +1,11 @@
+#include <string.h>
+#include <stddef.h>
+
+char *strchr(const char *s, const int n)
+{
+    for (; *s; s++)
+        if (*s == n)
+            return (char *)s;
+
+    return NULL;
+}
diff --git a/src/libc/src/strlen.c b/src/libc/src/strlen.c
new file mode 100644
index 0000000..43efcc5
--- /dev/null
+++ b/src/libc/src/strlen.c
@@ -0,0 +1,12 @@
+#include <string.h>
+#include <stddef.h>
+
+size_t strlen(const char *s)
+{
+    size_t ret = 0;
+
+    while (*s++)
+        ret++;
+
+    return ret;
+}
-- 
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