Merge branch 'sysprog21:main' into main

Author: G36maid

README.md

@@ -22,6 +22,11 @@ Linmo is a preemptive, multi-tasking operating system kernel built as an educati
 It offers a lightweight environment where all tasks share a single address space,
 keeping the memory footprint to a minimum.
 
+The name Linmo pays tribute to Lin Mo (林默), the mortal name of the Chinese sea goddess [Mazu](https://en.wikipedia.org/wiki/Mazu) (媽祖),
+who was a legendary figure from 10th-century Fujian later deified as the guardian of sailors and fishermen across the Chinese-speaking world.
+Just as Mazu was believed to provide calm and guidance in turbulent seas,
+Linmo aims to offer a structured learning environment within the constrained and often chaotic domain of embedded system education.
+
 Target Platform:
 * RISC-V (32-bit): RV32I architecture, tested with QEMU.
 

include/lib/libc.h

@@ -70,7 +70,7 @@ char *strncat(char *s1, const char *s2, int32_t n);
 int32_t strcmp(const char *s1, const char *s2);
 int32_t strncmp(const char *s1, const char *s2, int32_t n);
 char *strstr(const char *s1, const char *s2);
-int32_t strlen(const char *s1);
+size_t strlen(const char *s1);
 char *strchr(const char *s1, int32_t c);
 char *strpbrk(const char *s1, const char *s2);
 char *strsep(char **pp, const char *delim);

include/private/error.h

@@ -39,4 +39,4 @@ struct error_code {
     char *const desc;
 };
 
-extern struct error_code *perror;
+extern const struct error_code *const perror;

kernel/error.c

@@ -3,7 +3,7 @@
 #include "private/error.h"
 
 /* Ordered by enum value for quick linear search */
-static struct error_code error_desc[] = {
+static const struct error_code error_desc[] = {
     {ERR_OK, "no error"},
     {ERR_FAIL, "generic failure"},
 
@@ -35,4 +35,4 @@ static struct error_code error_desc[] = {
     {ERR_UNKNOWN, "unknown error"},
 };
 
-struct error_code *perror = error_desc;
+const struct error_code *const perror = error_desc;

lib/libc.c

@@ -20,14 +20,14 @@ static inline int byte_is_match(uint32_t w, uint32_t pat)
 }
 
 /* strlen that scans by words whenever possible for efficiency. */
-int32_t strlen(const char *s)
+size_t strlen(const char *s)
 {
     const char *p = s;
 
     /* Align pointer to word boundary (4 bytes) */
     while ((uint32_t) p & 3) {
         if (!*p) /* If null terminator is found byte-by-byte */
-            return (int32_t) (p - s);
+            return (size_t) (p - s);
         p++;
     }
 
@@ -42,7 +42,7 @@ int32_t strlen(const char *s)
     p = (const char *) w;
     while (*p) /* Scan byte-by-byte until the null terminator. */
         p++;
-    return (int32_t) (p - s); /* Return total length. */
+    return (size_t) (p - s); /* Return total length. */
 }
 
 void *memcpy(void *dst, const void *src, uint32_t len)
@@ -463,15 +463,16 @@ int32_t strtol(const char *s, char **end, int32_t base)
 }
 
 /* Base-10 string conversion without division or multiplication */
-static char* __str_base10(uint32_t value, char* buffer, int* length)
+static char *__str_base10(uint32_t value, char *buffer, int *length)
 {
     if (value == 0) {
         buffer[0] = '0';
         *length = 1;
         return buffer;
     }
 
-    char temp[12]; /* Max digits for 32-bit: 4,294,967,295 (10 digits) + sign + null */
+    /* Max digits for 32-bit: 4,294,967,295 (10 digits) + sign + null */
+    char tmp[12];
     int pos = 0;
 
     while (value > 0) {
@@ -487,29 +488,29 @@ static char* __str_base10(uint32_t value, char* buffer, int* length)
         q += t;
         r -= (((t << 2) + t) << 1);
 
-        temp[pos++] = '0' + r;
+        tmp[pos++] = '0' + r;
         value = q;
     }
 
     /* Reverse digits into output buffer */
     *length = pos;
     for (int i = 0; i < pos; i++) {
-        buffer[i] = temp[pos - 1 - i];
+        buffer[i] = tmp[pos - 1 - i];
     }
 
     return buffer;
 }
 
 /* Handle signed integers */
-static char* __str_base10_signed(int32_t value, char* buffer, int* length) {
+static char *__str_base10_signed(int32_t value, char *buffer, int *length)
+{
     if (value < 0) {
         buffer[0] = '-';
-        __str_base10((uint32_t)(-value), buffer + 1, length);
+        __str_base10((uint32_t) (-value), buffer + 1, length);
         (*length)++;
         return buffer;
-    } else {
-        return __str_base10((uint32_t)value, buffer, length);
     }
+    return __str_base10((uint32_t) value, buffer, length);
 }
 
 /* Converts string @s to an integer. */