osdep.c - qemu - Git at Google

 /*
  * QEMU low level functions
  *
  * Copyright (c) 2003 Fabrice Bellard
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */
 #include <stdlib.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <string.h>
 #include <errno.h>
 #include <unistd.h>

 #include "cpu.h"

 #if defined(__i386__) && !defined(CONFIG_SOFTMMU) && !defined(CONFIG_USER_ONLY)

 #include <sys/mman.h>
 #include <sys/ipc.h>

 /* When not using soft mmu, libc independant functions are needed for
    the CPU core because it needs to use alternates stacks and
    libc/thread incompatibles settings */

 #include <linux/unistd.h>

 #define QEMU_SYSCALL0(name) \
 { \
 long __res; \
 __asm__ volatile ("int $0x80" \
 	: "=a" (__res) \
 	: "0" (__NR_##name)); \
 return __res; \
 }

 #define QEMU_SYSCALL1(name,arg1) \
 { \
 long __res; \
 __asm__ volatile ("int $0x80" \
 	: "=a" (__res) \
 	: "0" (__NR_##name),"b" ((long)(arg1))); \
 return __res; \
 }

 #define QEMU_SYSCALL2(name,arg1,arg2) \
 { \
 long __res; \
 __asm__ volatile ("int $0x80" \
 	: "=a" (__res) \
 	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2))); \
 return __res; \
 }

 #define QEMU_SYSCALL3(name,arg1,arg2,arg3) \
 { \
 long __res; \
 __asm__ volatile ("int $0x80" \
 	: "=a" (__res) \
 	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
 		  "d" ((long)(arg3))); \
 return __res; \
 }

 #define QEMU_SYSCALL4(name,arg1,arg2,arg3,arg4) \
 { \
 long __res; \
 __asm__ volatile ("int $0x80" \
 	: "=a" (__res) \
 	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
 	  "d" ((long)(arg3)),"S" ((long)(arg4))); \
 return __res; \
 }

 #define QEMU_SYSCALL5(name,arg1,arg2,arg3,arg4,arg5) \
 { \
 long __res; \
 __asm__ volatile ("int $0x80" \
 	: "=a" (__res) \
 	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
 	  "d" ((long)(arg3)),"S" ((long)(arg4)),"D" ((long)(arg5))); \
 return __res; \
 }

 #define QEMU_SYSCALL6(name,arg1,arg2,arg3,arg4,arg5,arg6) \
 { \
 long __res; \
 __asm__ volatile ("push %%ebp ; movl %%eax,%%ebp ; movl %1,%%eax ; int $0x80 ; pop %%ebp" \
 	: "=a" (__res) \
 	: "i" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
 	  "d" ((long)(arg3)),"S" ((long)(arg4)),"D" ((long)(arg5)), \
 	  "0" ((long)(arg6))); \
 return __res; \
 }

 int qemu_write(int fd, const void *buf, size_t n)
 {
     QEMU_SYSCALL3(write, fd, buf, n);
 }


 /****************************************************************/
 /* shmat replacement */

 int qemu_ipc(int call, unsigned long first,
             unsigned long second, unsigned long third,
             void *ptr, unsigned long fifth)
 {
     QEMU_SYSCALL6(ipc, call, first, second, third, ptr, fifth);
 }

 #define SHMAT 21

 /* we must define shmat so that a specific address will be used when
    mapping the X11 ximage */
 void *shmat(int shmid, const void *shmaddr, int shmflg)
 {
     void *ptr;
     int ret;
     /* we give an address in the right memory area */
     if (!shmaddr)
         shmaddr = get_mmap_addr(8192 * 1024);
     ret = qemu_ipc(SHMAT, shmid, shmflg, (unsigned long)&ptr, (void *)shmaddr, 0);
     if (ret < 0)
         return NULL;
     return ptr;
 }

 /****************************************************************/
 /* memory allocation */

 //#define DEBUG_MALLOC

 #define MALLOC_BASE       0xab000000
 #define PHYS_RAM_BASE     0xac000000

 #define MALLOC_ALIGN      16
 #define BLOCK_HEADER_SIZE 16

 typedef struct MemoryBlock {
     struct MemoryBlock *next;
     unsigned long size; /* size of block, including header */
 } MemoryBlock;

 static MemoryBlock *first_free_block;
 static unsigned long malloc_addr = MALLOC_BASE;

 static void *malloc_get_space(size_t size)
 {
     void *ptr;
     size = TARGET_PAGE_ALIGN(size);
     ptr = mmap((void *)malloc_addr, size,
                PROT_WRITE | PROT_READ,
                MAP_PRIVATE | MAP_FIXED | MAP_ANON, -1, 0);
     if (ptr == MAP_FAILED)
         return NULL;
     malloc_addr += size;
     return ptr;
 }

 void *qemu_malloc(size_t size)
 {
     MemoryBlock *mb, *mb1, **pmb;
     void *ptr;
     size_t size1, area_size;

     if (size == 0)
         return NULL;

     size = (size + BLOCK_HEADER_SIZE + MALLOC_ALIGN - 1) & ~(MALLOC_ALIGN - 1);
     pmb = &first_free_block;
     for(;;) {
         mb = *pmb;
         if (mb == NULL)
             break;
         if (size <= mb->size)
             goto found;
         pmb = &mb->next;
     }
     /* no big enough blocks found: get new space */
     area_size = TARGET_PAGE_ALIGN(size);
     mb = malloc_get_space(area_size);
     if (!mb)
         return NULL;
     size1 = area_size - size;
     if (size1 > 0) {
         /* create a new free block */
         mb1 = (MemoryBlock *)((uint8_t *)mb + size);
         mb1->next = NULL;
         mb1->size = size1;
         *pmb = mb1;
     }
     goto the_end;
  found:
     /* a free block was found: use it */
     size1 = mb->size - size;
     if (size1 > 0) {
         /* create a new free block */
         mb1 = (MemoryBlock *)((uint8_t *)mb + size);
         mb1->next = mb->next;
         mb1->size = size1;
         *pmb = mb1;
     } else {
         /* suppress the first block */
         *pmb = mb->next;
     }
  the_end:
     mb->size = size;
     mb->next = NULL;
     ptr = ((uint8_t *)mb + BLOCK_HEADER_SIZE);
 #ifdef DEBUG_MALLOC
     qemu_printf("malloc: size=0x%x ptr=0x%lx\n", size, (unsigned long)ptr);
 #endif
     return ptr;
 }

 void qemu_free(void *ptr)
 {
     MemoryBlock *mb;

     if (!ptr)
         return;
     mb = (MemoryBlock *)((uint8_t *)ptr - BLOCK_HEADER_SIZE);
     mb->next = first_free_block;
     first_free_block = mb;
 }

 /****************************************************************/
 /* virtual memory allocation */

 unsigned long mmap_addr = PHYS_RAM_BASE;

 void *get_mmap_addr(unsigned long size)
 {
     unsigned long addr;
     addr = mmap_addr;
     mmap_addr += ((size + 4095) & ~4095) + 4096;
     return (void *)addr;
 }

 #else

 int qemu_write(int fd, const void *buf, size_t n)
 {
     int ret;
     ret = write(fd, buf, n);
     if (ret < 0)
         return -errno;
     else
         return ret;
 }

 void *get_mmap_addr(unsigned long size)
 {
     return NULL;
 }

 void qemu_free(void *ptr)
 {
     free(ptr);
 }

 void *qemu_malloc(size_t size)
 {
     return malloc(size);
 }

 #endif

 void *qemu_mallocz(size_t size)
 {
     void *ptr;
     ptr = qemu_malloc(size);
     if (!ptr)
         return NULL;
     memset(ptr, 0, size);
     return ptr;
 }

 /****************************************************************/
 /* printf support */

 static inline int qemu_isdigit(int c)
 {
     return c >= '0' && c <= '9';
 }

 #define OUTCHAR(c)	(buflen > 0? (--buflen, *buf++ = (c)): 0)

 /* from BSD ppp sources */
 int qemu_vsnprintf(char *buf, int buflen, const char *fmt, va_list args)
 {
     int c, i, n;
     int width, prec, fillch;
     int base, len, neg;
     unsigned long val = 0;
     const char *f;
     char *str, *buf0;
     char num[32];
     static const char hexchars[] = "0123456789abcdef";

     buf0 = buf;
     --buflen;
     while (buflen > 0) {
 	for (f = fmt; *f != '%' && *f != 0; ++f)
 	    ;
 	if (f > fmt) {
 	    len = f - fmt;
 	    if (len > buflen)
 		len = buflen;
 	    memcpy(buf, fmt, len);
 	    buf += len;
 	    buflen -= len;
 	    fmt = f;
 	}
 	if (*fmt == 0)
 	    break;
 	c = *++fmt;
 	width = prec = 0;
 	fillch = ' ';
 	if (c == '0') {
 	    fillch = '0';
 	    c = *++fmt;
 	}
 	if (c == '*') {
 	    width = va_arg(args, int);
 	    c = *++fmt;
 	} else {
 	    while (qemu_isdigit(c)) {
 		width = width * 10 + c - '0';
 		c = *++fmt;
 	    }
 	}
 	if (c == '.') {
 	    c = *++fmt;
 	    if (c == '*') {
 		prec = va_arg(args, int);
 		c = *++fmt;
 	    } else {
 		while (qemu_isdigit(c)) {
 		    prec = prec * 10 + c - '0';
 		    c = *++fmt;
 		}
 	    }
 	}
         /* modifiers */
         switch(c) {
         case 'l':
             c = *++fmt;
             break;
         default:
             break;
         }
         str = 0;
 	base = 0;
 	neg = 0;
 	++fmt;
 	switch (c) {
 	case 'd':
 	    i = va_arg(args, int);
 	    if (i < 0) {
 		neg = 1;
 		val = -i;
 	    } else
 		val = i;
 	    base = 10;
 	    break;
 	case 'o':
 	    val = va_arg(args, unsigned int);
 	    base = 8;
 	    break;
 	case 'x':
 	case 'X':
 	    val = va_arg(args, unsigned int);
 	    base = 16;
 	    break;
 	case 'p':
 	    val = (unsigned long) va_arg(args, void *);
 	    base = 16;
 	    neg = 2;
 	    break;
 	case 's':
 	    str = va_arg(args, char *);
 	    break;
 	case 'c':
 	    num[0] = va_arg(args, int);
 	    num[1] = 0;
 	    str = num;
 	    break;
 	default:
 	    *buf++ = '%';
 	    if (c != '%')
 		--fmt;		/* so %z outputs %z etc. */
 	    --buflen;
 	    continue;
 	}
 	if (base != 0) {
 	    str = num + sizeof(num);
 	    *--str = 0;
 	    while (str > num + neg) {
 		*--str = hexchars[val % base];
 		val = val / base;
 		if (--prec <= 0 && val == 0)
 		    break;
 	    }
 	    switch (neg) {
 	    case 1:
 		*--str = '-';
 		break;
 	    case 2:
 		*--str = 'x';
 		*--str = '0';
 		break;
 	    }
 	    len = num + sizeof(num) - 1 - str;
 	} else {
 	    len = strlen(str);
 	    if (prec > 0 && len > prec)
 		len = prec;
 	}
 	if (width > 0) {
 	    if (width > buflen)
 		width = buflen;
 	    if ((n = width - len) > 0) {
 		buflen -= n;
 		for (; n > 0; --n)
 		    *buf++ = fillch;
 	    }
 	}
 	if (len > buflen)
 	    len = buflen;
 	memcpy(buf, str, len);
 	buf += len;
 	buflen -= len;
     }
     *buf = 0;
     return buf - buf0;
 }

 void qemu_vprintf(const char *fmt, va_list ap)
 {
     char buf[1024];
     int len;

     len = qemu_vsnprintf(buf, sizeof(buf), fmt, ap);
     qemu_write(1, buf, len);
 }

 void qemu_printf(const char *fmt, ...)
 {
     va_list ap;
     va_start(ap, fmt);
     qemu_vprintf(fmt, ap);
     va_end(ap);
 }
	/*
	* QEMU low level functions
	*
	* Copyright (c) 2003 Fabrice Bellard
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/
	#include <stdlib.h>
	#include <stdio.h>
	#include <stdarg.h>
	#include <string.h>
	#include <errno.h>
	#include <unistd.h>

	#include "cpu.h"

	#if defined(__i386__) && !defined(CONFIG_SOFTMMU) && !defined(CONFIG_USER_ONLY)

	#include <sys/mman.h>
	#include <sys/ipc.h>

	/* When not using soft mmu, libc independant functions are needed for
	the CPU core because it needs to use alternates stacks and
	libc/thread incompatibles settings */

	#include <linux/unistd.h>

	#define QEMU_SYSCALL0(name) \
	{ \
	long __res; \
	__asm__ volatile ("int $0x80" \
	: "=a" (__res) \
	: "0" (__NR_##name)); \
	return __res; \
	}

	#define QEMU_SYSCALL1(name,arg1) \
	{ \
	long __res; \
	__asm__ volatile ("int $0x80" \
	: "=a" (__res) \
	: "0" (__NR_##name),"b" ((long)(arg1))); \
	return __res; \
	}

	#define QEMU_SYSCALL2(name,arg1,arg2) \
	{ \
	long __res; \
	__asm__ volatile ("int $0x80" \
	: "=a" (__res) \
	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2))); \
	return __res; \
	}

	#define QEMU_SYSCALL3(name,arg1,arg2,arg3) \
	{ \
	long __res; \
	__asm__ volatile ("int $0x80" \
	: "=a" (__res) \
	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
	"d" ((long)(arg3))); \
	return __res; \
	}

	#define QEMU_SYSCALL4(name,arg1,arg2,arg3,arg4) \
	{ \
	long __res; \
	__asm__ volatile ("int $0x80" \
	: "=a" (__res) \
	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
	"d" ((long)(arg3)),"S" ((long)(arg4))); \
	return __res; \
	}

	#define QEMU_SYSCALL5(name,arg1,arg2,arg3,arg4,arg5) \
	{ \
	long __res; \
	__asm__ volatile ("int $0x80" \
	: "=a" (__res) \
	: "0" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
	"d" ((long)(arg3)),"S" ((long)(arg4)),"D" ((long)(arg5))); \
	return __res; \
	}

	#define QEMU_SYSCALL6(name,arg1,arg2,arg3,arg4,arg5,arg6) \
	{ \
	long __res; \
	__asm__ volatile ("push %%ebp ; movl %%eax,%%ebp ; movl %1,%%eax ; int $0x80 ; pop %%ebp" \
	: "=a" (__res) \
	: "i" (__NR_##name),"b" ((long)(arg1)),"c" ((long)(arg2)), \
	"d" ((long)(arg3)),"S" ((long)(arg4)),"D" ((long)(arg5)), \
	"0" ((long)(arg6))); \
	return __res; \
	}

	int qemu_write(int fd, const void *buf, size_t n)
	{
	QEMU_SYSCALL3(write, fd, buf, n);
	}



	/****************************************************************/
	/* shmat replacement */

	int qemu_ipc(int call, unsigned long first,
	unsigned long second, unsigned long third,
	void *ptr, unsigned long fifth)
	{
	QEMU_SYSCALL6(ipc, call, first, second, third, ptr, fifth);
	}

	#define SHMAT 21

	/* we must define shmat so that a specific address will be used when
	mapping the X11 ximage */
	void shmat(int shmid, const void shmaddr, int shmflg)
	{
	void *ptr;
	int ret;
	/* we give an address in the right memory area */
	if (!shmaddr)
	shmaddr = get_mmap_addr(8192 * 1024);
	ret = qemu_ipc(SHMAT, shmid, shmflg, (unsigned long)&ptr, (void *)shmaddr, 0);
	if (ret < 0)
	return NULL;
	return ptr;
	}

	/****************************************************************/
	/* memory allocation */

	//#define DEBUG_MALLOC

	#define MALLOC_BASE 0xab000000
	#define PHYS_RAM_BASE 0xac000000

	#define MALLOC_ALIGN 16
	#define BLOCK_HEADER_SIZE 16

	typedef struct MemoryBlock {
	struct MemoryBlock *next;
	unsigned long size; /* size of block, including header */
	} MemoryBlock;

	static MemoryBlock *first_free_block;
	static unsigned long malloc_addr = MALLOC_BASE;

	static void *malloc_get_space(size_t size)
	{
	void *ptr;
	size = TARGET_PAGE_ALIGN(size);
	ptr = mmap((void *)malloc_addr, size,
	PROT_WRITE \| PROT_READ,
	MAP_PRIVATE \| MAP_FIXED \| MAP_ANON, -1, 0);
	if (ptr == MAP_FAILED)
	return NULL;
	malloc_addr += size;
	return ptr;
	}

	void *qemu_malloc(size_t size)
	{
	MemoryBlock mb, mb1, **pmb;
	void *ptr;
	size_t size1, area_size;

	if (size == 0)
	return NULL;

	size = (size + BLOCK_HEADER_SIZE + MALLOC_ALIGN - 1) & ~(MALLOC_ALIGN - 1);
	pmb = &first_free_block;
	for(;;) {
	mb = *pmb;
	if (mb == NULL)
	break;
	if (size <= mb->size)
	goto found;
	pmb = &mb->next;
	}
	/* no big enough blocks found: get new space */
	area_size = TARGET_PAGE_ALIGN(size);
	mb = malloc_get_space(area_size);
	if (!mb)
	return NULL;
	size1 = area_size - size;
	if (size1 > 0) {
	/* create a new free block */
	mb1 = (MemoryBlock )((uint8_t )mb + size);
	mb1->next = NULL;
	mb1->size = size1;
	*pmb = mb1;
	}
	goto the_end;
	found:
	/* a free block was found: use it */
	size1 = mb->size - size;
	if (size1 > 0) {
	/* create a new free block */
	mb1 = (MemoryBlock )((uint8_t )mb + size);
	mb1->next = mb->next;
	mb1->size = size1;
	*pmb = mb1;
	} else {
	/* suppress the first block */
	*pmb = mb->next;
	}
	the_end:
	mb->size = size;
	mb->next = NULL;
	ptr = ((uint8_t *)mb + BLOCK_HEADER_SIZE);
	#ifdef DEBUG_MALLOC
	qemu_printf("malloc: size=0x%x ptr=0x%lx\n", size, (unsigned long)ptr);
	#endif
	return ptr;
	}

	void qemu_free(void *ptr)
	{
	MemoryBlock *mb;

	if (!ptr)
	return;
	mb = (MemoryBlock )((uint8_t )ptr - BLOCK_HEADER_SIZE);
	mb->next = first_free_block;
	first_free_block = mb;
	}

	/****************************************************************/
	/* virtual memory allocation */

	unsigned long mmap_addr = PHYS_RAM_BASE;

	void *get_mmap_addr(unsigned long size)
	{
	unsigned long addr;
	addr = mmap_addr;
	mmap_addr += ((size + 4095) & ~4095) + 4096;
	return (void *)addr;
	}

	#else

	int qemu_write(int fd, const void *buf, size_t n)
	{
	int ret;
	ret = write(fd, buf, n);
	if (ret < 0)
	return -errno;
	else
	return ret;
	}

	void *get_mmap_addr(unsigned long size)
	{
	return NULL;
	}

	void qemu_free(void *ptr)
	{
	free(ptr);
	}

	void *qemu_malloc(size_t size)
	{
	return malloc(size);
	}

	#endif

	void *qemu_mallocz(size_t size)
	{
	void *ptr;
	ptr = qemu_malloc(size);
	if (!ptr)
	return NULL;
	memset(ptr, 0, size);
	return ptr;
	}

	/****************************************************************/
	/* printf support */

	static inline int qemu_isdigit(int c)
	{
	return c >= '0' && c <= '9';
	}

	#define OUTCHAR(c) (buflen > 0? (--buflen, *buf++ = (c)): 0)

	/* from BSD ppp sources */
	int qemu_vsnprintf(char buf, int buflen, const char fmt, va_list args)
	{
	int c, i, n;
	int width, prec, fillch;
	int base, len, neg;
	unsigned long val = 0;
	const char *f;
	char str, buf0;
	char num[32];
	static const char hexchars[] = "0123456789abcdef";

	buf0 = buf;
	--buflen;
	while (buflen > 0) {
	for (f = fmt; f != '%' && f != 0; ++f)
	;
	if (f > fmt) {
	len = f - fmt;
	if (len > buflen)
	len = buflen;
	memcpy(buf, fmt, len);
	buf += len;
	buflen -= len;
	fmt = f;
	}
	if (*fmt == 0)
	break;
	c = *++fmt;
	width = prec = 0;
	fillch = ' ';
	if (c == '0') {
	fillch = '0';
	c = *++fmt;
	}
	if (c == '*') {
	width = va_arg(args, int);
	c = *++fmt;
	} else {
	while (qemu_isdigit(c)) {
	width = width * 10 + c - '0';
	c = *++fmt;
	}
	}
	if (c == '.') {
	c = *++fmt;
	if (c == '*') {
	prec = va_arg(args, int);
	c = *++fmt;
	} else {
	while (qemu_isdigit(c)) {
	prec = prec * 10 + c - '0';
	c = *++fmt;
	}
	}
	}
	/* modifiers */
	switch(c) {
	case 'l':
	c = *++fmt;
	break;
	default:
	break;
	}
	str = 0;
	base = 0;
	neg = 0;
	++fmt;
	switch (c) {
	case 'd':
	i = va_arg(args, int);
	if (i < 0) {
	neg = 1;
	val = -i;
	} else
	val = i;
	base = 10;
	break;
	case 'o':
	val = va_arg(args, unsigned int);
	base = 8;
	break;
	case 'x':
	case 'X':
	val = va_arg(args, unsigned int);
	base = 16;
	break;
	case 'p':
	val = (unsigned long) va_arg(args, void *);
	base = 16;
	neg = 2;
	break;
	case 's':
	str = va_arg(args, char *);
	break;
	case 'c':
	num[0] = va_arg(args, int);
	num[1] = 0;
	str = num;
	break;
	default:
	*buf++ = '%';
	if (c != '%')
	--fmt; /* so %z outputs %z etc. */
	--buflen;
	continue;
	}
	if (base != 0) {
	str = num + sizeof(num);
	*--str = 0;
	while (str > num + neg) {
	*--str = hexchars[val % base];
	val = val / base;
	if (--prec <= 0 && val == 0)
	break;
	}
	switch (neg) {
	case 1:
	*--str = '-';
	break;
	case 2:
	*--str = 'x';
	*--str = '0';
	break;
	}
	len = num + sizeof(num) - 1 - str;
	} else {
	len = strlen(str);
	if (prec > 0 && len > prec)
	len = prec;
	}
	if (width > 0) {
	if (width > buflen)
	width = buflen;
	if ((n = width - len) > 0) {
	buflen -= n;
	for (; n > 0; --n)
	*buf++ = fillch;
	}
	}
	if (len > buflen)
	len = buflen;
	memcpy(buf, str, len);
	buf += len;
	buflen -= len;
	}
	*buf = 0;
	return buf - buf0;
	}

	void qemu_vprintf(const char *fmt, va_list ap)
	{
	char buf[1024];
	int len;

	len = qemu_vsnprintf(buf, sizeof(buf), fmt, ap);
	qemu_write(1, buf, len);
	}

	void qemu_printf(const char *fmt, ...)
	{
	va_list ap;
	va_start(ap, fmt);
	qemu_vprintf(fmt, ap);
	va_end(ap);
	}