sdk: Add sdk string functions

Signed-off-by: Ian Moffett <ian@mirocom.org>

src/Makefile

@@ -3,8 +3,14 @@
 # Provided under the BSD-3 clause
 #
 
+include mk/default.mk
+
 .PHONY: all
-all: m1x
+all: sdk m1x
+
+.PHONY: sdk
+sdk:
+	cd sdk/; make $(PASSDOWN_ARGS)
 
 .PHONY: m1x
 m1x:

src/m1x/arch/x86_64/Makefile

@@ -4,6 +4,7 @@
 #
 
 MISC_OFILES = $(shell find ../../ -name "*.o")
+SDK_OFILES = $(shell find ../../../sdk/ -name "*.o")
 
 ASMFILES = $(shell find . -name "*.S" | grep -v "boot")
 ASMOFILES = $(ASMFILES:.S=.S.o)
@@ -24,7 +25,7 @@ CFLAGS = 				\
 
 .PHONY: all
 all: $(OFILES) $(ASMOFILES)
-	$(LD) $(MISC_OFILES) -Tconf/link.ld -o $(KERN_BIN) $(LDFLAGS)
+	$(LD) $(MISC_OFILES) $(SDK_OFILES) -Tconf/link.ld -o $(KERN_BIN) $(LDFLAGS)
 
 %.S.o: %.S
 	$(CC) -c $< $(CFLAGS) -o $@

src/sdk/Makefile

@@ -0,0 +1,18 @@
+#
+# Copyright (c) 2026, Mirocom Laboratories
+# Provided under the BSD-3 clause
+#
+
+CFILES = $(shell find . -name "*.c")
+OFILES = $(CFILES:.c=.o)
+CC = ../$(SYS_CC)
+
+CFLAGS = 					\
+	$(SYS_CFLAGS) 			\
+	-Iinclude/
+
+.PHONY: all
+all:  $(OFILES)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -c $< -o $@

src/sdk/include/string.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * Provided under the BSD-3 clause
+ */
+
+#ifndef _SDK_STRING_H_
+#define _SDK_STRING_H_ 1
+
+#include <stdint.h>
+
+/*
+ * Obtain the length of a string in bytes excluding the NULL
+ * terminating character.
+ *
+ * @s:  String to obtain length from
+ *
+ * Return values of zero indicate error
+ */
+size_t strlen(const char *s);
+
+/*
+ * Copy memory from `src` to `dest`
+ *
+ * @dest:  Destination buffer
+ * @src:   Source buffer
+ * @count: Number of bytes to copy
+ *
+ * Returns `dest' on success
+ */
+void *memcpy(void *dest, const void *src, size_t count);
+
+/*
+ * Fill a buffer `s` with `n` bytes of `c`
+ *
+ * @s: Buffer to fill
+ * @c: Data to fill with
+ * @n: Number of bytes to fill
+ *
+ * Returns `s` on success
+ */
+void *memset(void *s, int c, size_t n);
+
+#endif  /* !_SDK_STRING_H_ */

src/sdk/string/memcpy.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * Provided under the BSD-3 clause
+ */
+
+#define _M1X_SOURCE
+#include <string.h>
+
+void *
+memcpy(void *dest, const void *src, size_t count)
+{
+    if (dest == NULL || src == NULL) {
+        return NULL;
+    }
+
+    for (size_t i = 0; i < count; ++i) {
+        ((char *)dest)[i] = ((char *)src)[i];
+    }
+
+    return dest;
+}

src/sdk/string/memset.c

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * Provided under the BSD-3 clause
+ */
+
+#define _M1X_SOURCE
+#include <string.h>
+
+void
+*memset(void *s, int c, size_t n)
+{
+    if (s == NULL) {
+        return NULL;
+    }
+
+    for (size_t i = 0; i < n; ++i) {
+        ((uint8_t *)s)[i] = c;
+    }
+
+    return s;
+}

src/sdk/string/strlen.c

@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * Provided under the BSD-3 clause
+ */
+
+#define _M1X_SOURCE
+#include <string.h>
+
+size_t
+strlen(const char *s)
+{
+    size_t length = 0;
+    const char *p = s;
+
+    while ((*p++) != '\0') {
+        ++length;
+    }
+
+    return length;
+}