add some standard libc functions

PauloMigAlmeida · Dec 16, 2021 · b540e29 · b540e29
1 parent 83061e8
commit b540e29
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Showing 12 changed files with 248 additions and 3 deletions.
diff --git a/include/libc/internals/syscall.h b/include/libc/internals/syscall.h
@@ -24,5 +24,6 @@ long syscall(long nr_number, ...);
 #define __NR_read     0
 #define __NR_write    1
 #define __NR_getpid   39
+#define __NR_time     201
 
 #endif /* INCLUDE_LIBC_INTERNAL_SYSCALL_H_ */
diff --git a/include/libc/stdlib.h b/include/libc/stdlib.h
@@ -14,4 +14,9 @@ int rand(void);
 int rand_r(unsigned int *seedp);
 void srand(unsigned int s);
 
+char* ltoa(long value, char *str, int radix);
+
+int abs(int value);
+
+
 #endif /* INCLUDE_LIBC_STDLIB_H_ */
diff --git a/include/libc/string.h b/include/libc/string.h
@@ -0,0 +1,19 @@
+/*
+ * string.h
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#ifndef INCLUDE_LIBC_STRING_H_
+#define INCLUDE_LIBC_STRING_H_
+
+#include "libc/compiler/freestanding.h"
+
+void* memcpy(void *dst, const void *src, size_t size);
+void* memset(void *buf, char value, size_t size);
+void* memmove(void *dst, void *src, size_t size);
+size_t strlen(const char *buf);
+void strrev(char *str, size_t length);
+
+#endif /* INCLUDE_LIBC_STRING_H_ */
diff --git a/src/libc/stdlib/Makefile b/src/libc/stdlib/Makefile
@@ -1,5 +1,5 @@
 #----------------------------------------------------------------------------
-# AlmeidaOS libc/rand makefile
+# AlmeidaOS libc/stdlib makefile
 #----------------------------------------------------------------------------
 
 DIR_ROOT	:= $(CURDIR)/../../../
@@ -10,15 +10,15 @@ include $(DIR_ROOT)/scripts/config.mk
 ASFLAGS		:= -f elf64
 
 DIR_SRC_SUBSYSTEMS := $(shell find $(CURDIR)/* -maxdepth 1 -type d)
-DIR_TARGET	:= $(DIR_BUILD)/libc/rand
+DIR_TARGET	:= $(DIR_BUILD)/libc/stdlib
 
 SRC_C_FILES	:= $(wildcard *.c)
 BIN_C_FILES	:= $(SRC_C_FILES:%.c=$(DIR_TARGET)/%.o)
 
 SRC_ASM_FILES	:= $(wildcard *.asm)
 BIN_ASM_FILES	:= $(SRC_ASM_FILES:%.asm=$(DIR_TARGET)/%.o)
 
-TAG 		:= [libc/rand]
+TAG 		:= [libc/stdlib]
 
 all: mkdir compile
 	@echo "$(TAG) Compiled successfully"

diff --git a/src/libc/stdlib/abs.c b/src/libc/stdlib/abs.c
@@ -0,0 +1,17 @@
+/*
+ * abs.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/stdlib.h"
+
+int abs(int value) {
+    /*
+     * C99 abs:"if the result cannot be represented, the behavior is undefined."
+     * So I decided not to handle 2-complement's edge case such as -2147483648
+     */
+    int const mask = value >> (sizeof(int) * CHAR_BIT - 1);
+    return (value + mask) ^ mask;
+}
diff --git a/src/libc/stdlib/ltoa.c b/src/libc/stdlib/ltoa.c
@@ -0,0 +1,47 @@
+/*
+ * ltoa.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/stdlib.h"
+#include "libc/string.h"
+
+char* ltoa(long value, char *str, int radix) {
+    // Check for supported base.
+    if (radix != 8 && radix != 10 && radix != 16) {
+        *str = '\0';
+        return str;
+    }
+
+    int i = 0;
+    bool is_negative = false;
+
+    /* handle edge case */
+    if (value == 0) {
+        str[i++] = '0';
+        str[i] = '\0';
+        return str;
+    }
+
+    /* negative numbers are handled only with base 10 */
+    if (value < 0 && radix == 10) {
+        is_negative = true;
+        value = abs(value);
+    }
+
+    while (value != 0) {
+        int rem = value % radix;
+        str[i++] = (rem > 9) ? (rem - 10) + 'a' : rem + '0';
+        value = value / radix;
+    }
+
+    if (is_negative)
+        str[i++] = '-';
+
+    str[i] = '\0';
+    strrev(str, i);
+
+    return str;
+}
diff --git a/src/libc/string/Makefile b/src/libc/string/Makefile
@@ -0,0 +1,49 @@
+#----------------------------------------------------------------------------
+# AlmeidaOS libc/string makefile
+#----------------------------------------------------------------------------
+
+DIR_ROOT	:= $(CURDIR)/../../../
+
+include $(DIR_ROOT)/scripts/config.mk
+
+# override AS flags from $(DIR_ROOT)/scripts/config.mk
+ASFLAGS		:= -f elf64
+
+DIR_SRC_SUBSYSTEMS := $(shell find $(CURDIR)/* -maxdepth 1 -type d)
+DIR_TARGET	:= $(DIR_BUILD)/libc/string
+
+SRC_C_FILES	:= $(wildcard *.c)
+BIN_C_FILES	:= $(SRC_C_FILES:%.c=$(DIR_TARGET)/%.o)
+
+SRC_ASM_FILES	:= $(wildcard *.asm)
+BIN_ASM_FILES	:= $(SRC_ASM_FILES:%.asm=$(DIR_TARGET)/%.o)
+
+TAG 		:= [libc/string]
+
+all: mkdir compile
+	@echo "$(TAG) Compiled successfully"
+
+.PHONY: mkdir
+mkdir:
+	@mkdir -p $(DIR_TARGET)
+
+.PHONY: clean
+clean:
+	@rm -f $(BIN_C_FILES)
+
+.PHONY: compile
+compile: $(BIN_C_FILES) $(BIN_ASM_FILES) $(DIR_SRC_SUBSYSTEMS)
+
+$(BIN_C_FILES): $(DIR_TARGET)/%.o: %.c
+	@echo "$(TAG) Compiling $<"
+	@$(CC) $(CCFLAGS) -I$(DIR_INCLUDE) -c $< -o $@
+
+$(BIN_ASM_FILES): $(DIR_TARGET)/%.o: %.asm
+	@echo "$(TAG) Assembling $<"
+	@$(AS) $(ASFLAGS) $< -o $@
+
+.PHONY: $(DIR_SRC_SUBSYSTEMS)
+$(DIR_SRC_SUBSYSTEMS):
+	@$(MAKE) $(MAKE_FLAGS) --directory=$@
+
+
diff --git a/src/libc/string/memcpy.c b/src/libc/string/memcpy.c
@@ -0,0 +1,23 @@
+/*
+ * memcpy.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/string.h"
+
+void* memcpy(void *dst, const void *src, size_t size) {
+
+    long d0, d1, d2;
+    asm volatile(
+            "rep movsq \n\t"
+            "movq rcx, %[remainder] \n\t"
+            "rep movsb \n\t"
+            : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+            : "0" (size >> 3), [remainder] "g" (size & 7), "1" (dst), "2" (src)
+            : "memory"
+    );
+
+    return dst;
+}
diff --git a/src/libc/string/memmove.c b/src/libc/string/memmove.c
@@ -0,0 +1,30 @@
+/*
+ * memmove.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/string.h"
+
+void* memmove(void *dst, void *src, size_t size) {
+    char *t_dst = dst;
+    char *t_src = src;
+
+    /* sanity check */
+    if (t_src == t_dst)
+        return dst;
+
+    memcpy(t_dst, t_src, size);
+
+    if ((t_dst > t_src && (t_src + size) < t_dst) || (t_src > t_dst && (t_dst + size) < t_src)) {
+        /* they don't interset */
+        memset(t_src, 0, size);
+    } else if (t_dst > t_src) {
+        memset(t_src, 0, size - (t_dst - t_src));
+    } else {
+        memset(t_src + ((t_src + size) - (t_dst + size)), 0, (t_src + size) - (t_dst + size));
+    }
+
+    return dst;
+}
diff --git a/src/libc/string/memset.c b/src/libc/string/memset.c
@@ -0,0 +1,18 @@
+/*
+ * memset.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/string.h"
+
+void* memset(void *buf, char value, size_t size) {
+    asm volatile(
+            "rep stosb \n\t"
+            : "=&D" (buf)
+            : "a" (value), "c"(size)
+            : "memory"
+    );
+    return buf;
+}
diff --git a/src/libc/string/strlen.c b/src/libc/string/strlen.c
@@ -0,0 +1,16 @@
+/*
+ * strlen.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/string.h"
+
+size_t strlen(const char *buf) {
+    /* we don't count NUL-terminator */
+    size_t len = 0;
+    for (; *(buf + len) != '\0'; len++)
+        /* nothing */ ;
+    return len;
+}
diff --git a/src/libc/string/strrev.c b/src/libc/string/strrev.c
@@ -0,0 +1,20 @@
+/*
+ * strrev.c
+ *
+ *  Created on: 16/12/2021
+ *      Author: Paulo Almeida
+ */
+
+#include "libc/string.h"
+
+void strrev(char *str, size_t length) {
+    /* str is expected to be NUL-terminated */
+    if (length < 2)
+        return;
+
+    for (size_t start = 0, end = length - 1; start < length / 2; start++, end--) {
+        char tmp = *(str + start);
+        *(str + start) = *(str + end);
+        *(str + end) = tmp;
+    }
+}