Commit 03170c04 authored by Nicolas Pitre's avatar Nicolas Pitre Committed by Andrew Boie
Browse files

string.c: make it 64-bit compatible 



Casting a pointer to an int produces warnings with 64-bit targets.
Furthermore, an int is not always the optimal memory element that
can be copied in that case.

Let's use uintptr_t to cast pointers to integers for alignment
determination purposes, and mem_word_t to denote the optimal memory
"word" that can be copied on the platform.

The mem_word_t definition is equivalent to uintptr_t by default.
However, some 32-bit targets such as ARM platforms with the LDRD/STRD
instructions could benefit from word_t being an uint64_t.

Signed-off-by: default avatarNicolas Pitre <npitre@baylibre.com>
parent 98627ccc

lib/libc/minimal/include/sys/types.h

+14 −0
Original line number Diff line number Diff line
@@ -45,4 +45,18 @@ typedef int off_t; 
typedef int64_t time_t;

typedef int32_t suseconds_t;



#if !defined(__mem_word_t_defined)

#define __mem_word_t_defined



/*

 * The mem_word_t should match the optimal memory access word width

 * on the target platform. Here we defaults it to uintptr_t.

 */



typedef uintptr_t mem_word_t;



#define Z_MEM_WORD_T_WIDTH __INTPTR_WIDTH__



#endif



#endif /* ZEPHYR_LIB_LIBC_MINIMAL_INCLUDE_SYS_TYPES_H_ */

lib/libc/minimal/source/string/string.c

+17 −11
Original line number Diff line number Diff line
@@ -7,6 +7,8 @@ 
 */



#include <string.h>

#include <stdint.h>

#include <sys/types.h>



/**

 *
@@ -241,12 +243,13 @@ void *memcpy(void *_MLIBC_RESTRICT d, const void *_MLIBC_RESTRICT s, size_t n) 


	unsigned char *d_byte = (unsigned char *)d;

	const unsigned char *s_byte = (const unsigned char *)s;

	const uintptr_t mask = sizeof(mem_word_t) - 1;



	if ((((unsigned int)d ^ (unsigned int)s_byte) & 0x3) == 0U) {

	if ((((uintptr_t)d ^ (uintptr_t)s_byte) & mask) == 0) {



		/* do byte-sized copying until word-aligned or finished */



		while (((unsigned int)d_byte) & 0x3) {

		while (((uintptr_t)d_byte) & mask) {

			if (n == 0) {

				return d;

			}
@@ -256,12 +259,12 @@ void *memcpy(void *_MLIBC_RESTRICT d, const void *_MLIBC_RESTRICT s, size_t n) 


		/* do word-sized copying as long as possible */



		unsigned int *d_word = (unsigned int *)d_byte;

		const unsigned int *s_word = (const unsigned int *)s_byte;

		mem_word_t *d_word = (mem_word_t *)d_byte;

		const mem_word_t *s_word = (const mem_word_t *)s_byte;



		while (n >= sizeof(unsigned int)) {

		while (n >= sizeof(mem_word_t)) {

			*(d_word++) = *(s_word++);

			n -= sizeof(unsigned int);

			n -= sizeof(mem_word_t);

		}



		d_byte = (unsigned char *)d_word;
@@ -292,7 +295,7 @@ void *memset(void *buf, int c, size_t n) 
	unsigned char *d_byte = (unsigned char *)buf;

	unsigned char c_byte = (unsigned char)c;



	while (((unsigned int)d_byte) & 0x3) {

	while (((uintptr_t)d_byte) & (sizeof(mem_word_t) - 1)) {

		if (n == 0) {

			return buf;

		}
@@ -302,15 +305,18 @@ void *memset(void *buf, int c, size_t n) 


	/* do word-sized initialization as long as possible */



	unsigned int *d_word = (unsigned int *)d_byte;

	unsigned int c_word = (unsigned int)(unsigned char)c;

	mem_word_t *d_word = (mem_word_t *)d_byte;

	mem_word_t c_word = (mem_word_t)c_byte;



	c_word |= c_word << 8;

	c_word |= c_word << 16;

#if Z_MEM_WORD_T_WIDTH > 32

	c_word |= c_word << 32;

#endif



	while (n >= sizeof(unsigned int)) {

	while (n >= sizeof(mem_word_t)) {

		*(d_word++) = c_word;

		n -= sizeof(unsigned int);

		n -= sizeof(mem_word_t);

	}



	/* do byte-sized initialization until finished */

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