make a bootable BIOS
includes source from kvm-unit-tests
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/Makefile b/Makefile
index 0fb6c95..2e8a142 100644
--- a/Makefile
+++ b/Makefile
@@ -1,11 +1,14 @@
obj16-y = e820.o int10.o int15.o
-obj-y = $(obj16-y) entry.o
+obj-y = $(obj16-y) entry.o main.o string.o printf.o cstart.o
all-y = bios.bin
+CFLAGS := -O2 -Wall -g
+
BIOS_CFLAGS += -m32
BIOS_CFLAGS += -march=i386
BIOS_CFLAGS += -mregparm=3
-BIOS_CFLAGS += -fno-stack-protector
+BIOS_CFLAGS += -fno-stack-protector -fno-delete-null-pointer-checks
+BIOS_CFLAGS += -ffreestanding
BIOS_CFLAGS += -Iinclude
$(obj16-y): BIOS_CFLAGS += -include code16gcc.h
@@ -17,11 +20,11 @@
%.o: %.S
$(CC) $(CFLAGS) $(BIOS_CFLAGS) -c -s $< -o $@
-bios.bin.elf: $(obj-y) rom.ld.S
- $(LD) -T rom.ld.S -o bios.bin.elf $(obj-y)
+bios.bin.elf: $(obj-y) flat.lds
+ $(LD) -T flat.lds -o bios.bin.elf $(obj-y)
bios.bin: bios.bin.elf
objcopy -O binary bios.bin.elf bios.bin
clean:
- rm $(obj-y) $(all-y) bios.bin.elf
+ rm -f $(obj-y) $(all-y) bios.bin.elf
diff --git a/cstart.S b/cstart.S
new file mode 100644
index 0000000..5ca61c8
--- /dev/null
+++ b/cstart.S
@@ -0,0 +1,38 @@
+.code16gcc
+#include "assembly.h"
+.section .init
+ENTRY(pm_entry)
+ xor %ax, %ax
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %ss
+ mov $0x7c00, %sp
+
+ mov %cr0, %eax
+ or $1, %eax
+ mov %eax, %cr0
+ lgdtl %cs:0xff80 + gdt32_descr - pm_entry
+ ljmpl $8, $0xffffff80 + 2f - pm_entry
+2:
+ .code32
+ mov $16, %ax
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %ss
+ ljmp $8, $0xffff0000
+
+gdt32:
+ .quad 0
+ .quad 0x00cf9b000000ffff // flat 32-bit code segment
+ .quad 0x00cf93000000ffff // flat 32-bit data segment
+gdt32_end:
+
+gdt32_descr:
+ .word gdt32_end - gdt32 - 1
+ .long 0xffffff80 + gdt32 - pm_entry
+ENTRY_END(pm_entry)
+
+ .code16gcc
+ .section .resetvector
+ jmp pm_entry
+
diff --git a/e820.c b/e820.c
index 4eab157..6271353 100644
--- a/e820.c
+++ b/e820.c
@@ -27,35 +27,32 @@
return v;
}
+struct e820map e820;
+
bioscall void e820_query_map(struct biosregs *regs)
{
- struct e820map *e820;
uint32_t map_size;
uint16_t fs_seg;
uint32_t ndx;
- e820 = (struct e820map *)E820_MAP_START;
- fs_seg = flat_to_seg16(E820_MAP_START);
+ fs_seg = flat_to_seg16((uintptr_t) &e820);
set_fs(fs_seg);
ndx = regs->ebx;
- map_size = rdfs32(flat_to_off16((uint32_t)&e820->nr_map, fs_seg));
+ map_size = rdfs32(flat_to_off16((uintptr_t) &e820.nr_map));
if (ndx < map_size) {
uint32_t start;
unsigned int i;
uint8_t *p;
- fs_seg = flat_to_seg16(E820_MAP_START);
- set_fs(fs_seg);
-
- start = (uint32_t)&e820->map[ndx];
+ start = flat_to_off16((uintptr_t)&e820.map[ndx]);
p = (void *) regs->edi;
for (i = 0; i < sizeof(struct e820entry); i++)
- *p++ = rdfs8(flat_to_off16(start + i, fs_seg));
+ *p++ = rdfs8(start + i);
}
regs->eax = SMAP;
diff --git a/entry.S b/entry.S
index a192c7d..89fa51e 100644
--- a/entry.S
+++ b/entry.S
@@ -84,12 +84,3 @@
IRET
ENTRY_END(bios_int15)
-
-ENTRY(real_entry)
- cli
- hlt
-ENTRY_END(real_entry)
-
- ORG(fff0)
- jmp real_entry
-
diff --git a/flat.lds b/flat.lds
new file mode 100644
index 0000000..d12b835
--- /dev/null
+++ b/flat.lds
@@ -0,0 +1,24 @@
+OUTPUT_ARCH(i386)
+
+SECTIONS
+{
+ . = 1024K - 64K;
+ .text : { *(.text.startup) *(.text) *(.text.*) }
+ . = ALIGN(4K);
+ .data : { *(.data) }
+ . = ALIGN(16);
+ .rodata : { *(.rodata) }
+ . = ALIGN(16);
+ .bss : { *(.bss) }
+ . = ALIGN(4K);
+ . = 1024K - 128;
+ .init : {
+ *(.init);
+ . = 128 - 16;
+ *(.resetvector);
+ . = 128;
+ }
+}
+
+ENTRY(main)
+
diff --git a/include/assembly.h b/include/assembly.h
index 3601024..6965583 100644
--- a/include/assembly.h
+++ b/include/assembly.h
@@ -3,6 +3,10 @@
#define __ASSEMBLY__
+#define BIOS2FLAT(x) ((x) - _start + 0xf0000)
+#define BIOS2FLATROM(x) ((x) - _start + 0xffff0000)
+_start = 0
+
#define ORG(x) \
.section .fixedaddr._##x
diff --git a/include/bios.h b/include/bios.h
index 153c887..22a912a 100644
--- a/include/bios.h
+++ b/include/bios.h
@@ -4,32 +4,6 @@
#include <inttypes.h>
/*
- * X86-32 Memory Map (typical)
- * start end
- * Real Mode Interrupt Vector Table 0x00000000 0x000003FF
- * BDA area 0x00000400 0x000004FF
- * Conventional Low Memory 0x00000500 0x0009FBFF
- * EBDA area 0x0009FC00 0x0009FFFF
- * VIDEO RAM 0x000A0000 0x000BFFFF
- * VIDEO ROM (BIOS) 0x000C0000 0x000C7FFF
- * ROMs & unus. space (mapped hw & misc)0x000C8000 0x000EFFFF 160 KiB (typically)
- * Motherboard BIOS 0x000F0000 0x000FFFFF
- * Extended Memory 0x00100000 0xFEBFFFFF
- * Reserved (configs, ACPI, PnP, etc) 0xFEC00000 0xFFFFFFFF
- */
-
-#define REAL_MODE_IVT_BEGIN 0x00000000
-#define REAL_MODE_IVT_END 0x000003ff
-
-#define BDA_START 0x00000400
-#define BDA_END 0x000004ff
-
-#define EBDA_START 0x0009fc00
-#define EBDA_END 0x0009ffff
-
-#define E820_MAP_START EBDA_START
-
-/*
* When interfacing with assembler code we need to be sure how
* arguments are passed in real mode.
*/
@@ -37,8 +11,6 @@
#ifndef __ASSEMBLER__
-#include <linux/types.h>
-
struct biosregs {
uint32_t eax;
uint32_t ebx;
@@ -59,6 +31,14 @@
extern bioscall void int15_handler(struct biosregs *regs);
extern bioscall void e820_query_map(struct biosregs *regs);
+extern struct e820map e820;
+
+static inline void __attribute__((noreturn)) panic(void)
+{
+ asm volatile("cli; hlt");
+ for(;;);
+}
+
#endif
#endif /* BIOS_H_ */
diff --git a/include/ioport.h b/include/ioport.h
new file mode 100644
index 0000000..bbec982
--- /dev/null
+++ b/include/ioport.h
@@ -0,0 +1,50 @@
+#ifndef _IOPORT_H
+#define _IOPORT_H 1
+
+static inline void outsb(unsigned short port, void *buf, int len)
+{
+ asm volatile("rep outsb %%ds:(%0), %3" : "+S" (buf), "+c" (len) : "m"(buf), "Nd"(port), "0" (buf), "1" (len));
+}
+
+static inline void insb(void *buf, unsigned short port, int len)
+{
+ asm volatile("rep insb %3, %%es:(%0)" : "+D" (buf), "+c" (len), "=m"(buf) : "Nd"(port), "0" (buf), "1" (len));
+}
+
+static inline unsigned char inb(unsigned short port)
+{
+ unsigned char val;
+ asm volatile("inb %1, %0" : "=a"(val) : "Nd"(port));
+ return val;
+}
+
+static inline unsigned short inw(unsigned short port)
+{
+ unsigned short val;
+ asm volatile("inw %1, %0" : "=a"(val) : "Nd"(port));
+ return val;
+}
+
+static inline unsigned inl(unsigned short port)
+{
+ unsigned val;
+ asm volatile("inl %1, %0" : "=a"(val) : "Nd"(port));
+ return val;
+}
+
+static inline void outb(unsigned short port, unsigned char val)
+{
+ asm volatile("outb %0, %1" : : "a"(val), "Nd"(port));
+}
+
+static inline void outw(unsigned short port, unsigned short val)
+{
+ asm volatile("outw %0, %1" : : "a"(val), "Nd"(port));
+}
+
+static inline void outl(unsigned short port, unsigned val)
+{
+ asm volatile("outl %0, %1" : : "a"(val), "Nd"(port));
+}
+
+#endif
diff --git a/include/pci.h b/include/pci.h
new file mode 100644
index 0000000..e6b445c
--- /dev/null
+++ b/include/pci.h
@@ -0,0 +1,44 @@
+#ifndef _PCI_H
+#define _PCI_H
+
+#include "ioport.h"
+
+static inline void pci_config_writel(uint16_t bdf, uint32_t addr, uint32_t val)
+{
+ outl(0xcf8, 0x80000000 | (bdf << 8) | (addr & 0xfc));
+ outl(0xcfc, val);
+}
+
+void pci_config_writew(uint16_t bdf, uint32_t addr, uint16_t val)
+{
+ outl(0xcf8, 0x80000000 | (bdf << 8) | (addr & 0xfc));
+ outw(0xcfc | (addr & 2), val);
+}
+
+void pci_config_writeb(uint16_t bdf, uint32_t addr, uint8_t val)
+{
+ outl(0xcf8, 0x80000000 | (bdf << 8) | (addr & 0xfc));
+ outb(0xcfc | (addr & 3), val);
+}
+
+uint32_t pci_config_readl(uint16_t bdf, uint32_t addr)
+{
+ outl(0xcf8, 0x80000000 | (bdf << 8) | (addr & 0xfc));
+ return inl(0xcfc);
+}
+
+uint16_t pci_config_readw(uint16_t bdf, uint32_t addr)
+{
+ outl(0xcf8, 0x80000000 | (bdf << 8) | (addr & 0xfc));
+ return inw(0xcfc | (addr & 2));
+}
+
+uint8_t pci_config_readb(uint16_t bdf, uint32_t addr)
+{
+ outl(0xcf8, 0x80000000 | (bdf << 8) | (addr & 0xfc));
+ return inb(0xcfc | (addr & 3));
+}
+
+#define PCI_VENDOR_ID 0
+
+#endif
diff --git a/include/segment.h b/include/segment.h
index 694eb4b..7b68706 100644
--- a/include/segment.h
+++ b/include/segment.h
@@ -8,12 +8,12 @@
static inline uint16_t flat_to_seg16(uint32_t address)
{
- return address >> 4;
+ return (address >> 4) & 0xf000;
}
-static inline uint16_t flat_to_off16(uint32_t address, uint32_t segment)
+static inline uint16_t flat_to_off16(uint32_t address)
{
- return address - (segment << 4);
+ return address & 65535;
}
#endif /* KVM_SEGMENT_H */
diff --git a/include/stdio.h b/include/stdio.h
new file mode 100644
index 0000000..c154933
--- /dev/null
+++ b/include/stdio.h
@@ -0,0 +1,11 @@
+#ifndef BIOS_STDIO_H
+#define BIOS_STDIO_H 1
+
+#include <stdarg.h>
+
+extern int puts(const char *s);
+extern int printf(const char *fmt, ...);
+extern int snprintf(char *buf, int size, const char *fmt, ...);
+extern int vsnprintf(char *buf, int size, const char *fmt, va_list va);
+
+#endif
diff --git a/include/stdlib.h b/include/stdlib.h
new file mode 100644
index 0000000..8de2f31
--- /dev/null
+++ b/include/stdlib.h
@@ -0,0 +1,6 @@
+#ifndef BIOS_STDLIB_H
+#define BIOS_STDLIB_H 1
+
+extern long atol(const char *ptr);
+
+#endif
diff --git a/include/string.h b/include/string.h
new file mode 100644
index 0000000..962b07e
--- /dev/null
+++ b/include/string.h
@@ -0,0 +1,18 @@
+#ifndef _STRING_H
+#define _STRING_H
+
+#include <stddef.h>
+
+unsigned long strlen(const char *buf);
+char *strcat(char *dest, const char *src);
+char *strcpy(char *dest, const char *src);
+int strcmp(const char *a, const char *b);
+char *strchr(const char *s, int c);
+char *strstr(const char *s1, const char *s2);
+void *memset(void *s, int c, size_t n);
+void *memcpy(void *dest, const void *src, size_t n);
+int memcmp(const void *s1, const void *s2, size_t n);
+void *memmove(void *dest, const void *src, size_t n);
+void *memchr(const void *s, int c, size_t n);
+
+#endif
diff --git a/int10.c b/int10.c
index 9d9604c..0e506cc 100644
--- a/int10.c
+++ b/int10.c
@@ -1,10 +1,6 @@
#include "bios.h"
#include "segment.h"
-
-static inline void outb(unsigned short port, unsigned char val)
-{
- asm volatile("outb %0, %1" : : "a"(val), "Nd"(port));
-}
+#include "ioport.h"
/*
* It's probably much more useful to make this print to the serial
diff --git a/main.c b/main.c
new file mode 100644
index 0000000..eeb21fd
--- /dev/null
+++ b/main.c
@@ -0,0 +1,49 @@
+#include "bios.h"
+#include "pci.h"
+#include "string.h"
+
+#define PCI_VENDOR_ID_INTEL 0x8086
+#define PCI_DEVICE_ID_INTEL_82441 0x1237
+#define PCI_DEVICE_ID_INTEL_Q35_MCH 0x29c0
+
+#define I440FX_PAM0 0x59
+#define Q35_HOST_BRIDGE_PAM0 0x90
+
+static void make_bios_writable(void)
+{
+ const int bdf = 0;
+ const uint8_t *bios_start = (uint8_t *)0xffff0000;
+ uint8_t *low_start = (uint8_t *)0xf0000;
+ int pambase;
+
+ uint32_t id = pci_config_readl(bdf, 0);
+ if (id == (PCI_VENDOR_ID_INTEL | (PCI_DEVICE_ID_INTEL_82441 << 16)))
+ pambase = I440FX_PAM0;
+ else if (id == (PCI_VENDOR_ID_INTEL | (PCI_DEVICE_ID_INTEL_Q35_MCH << 16)))
+ pambase = Q35_HOST_BRIDGE_PAM0;
+ else
+ panic();
+
+ // Make ram from 0xc0000-0xf0000 read-write
+ int i;
+ for (i=0; i<6; i++) {
+ int pam = pambase + 1 + i;
+ pci_config_writeb(bdf, pam, 0x33);
+ }
+
+ // Make ram from 0xf0000-0x100000 read-write and shadow BIOS
+ // We're still running from 0xffff0000
+ pci_config_writeb(bdf, pambase, 0x30);
+ memcpy(low_start, bios_start, 0x10000);
+}
+
+
+int main(void)
+{
+ make_bios_writable();
+ // extract_acpi();
+ // extract_smbios();
+ // extract_kernel();
+ // boot_linux();
+ panic();
+}
diff --git a/printf.c b/printf.c
new file mode 100644
index 0000000..a171d24
--- /dev/null
+++ b/printf.c
@@ -0,0 +1,256 @@
+#include "bios.h"
+#include "stdio.h"
+#include "string.h"
+#include "stdlib.h"
+#include "ioport.h"
+
+typedef struct pstream {
+ char *buffer;
+ int remain;
+ int added;
+} pstream_t;
+
+typedef struct strprops {
+ char pad;
+ int npad;
+} strprops_t;
+
+static void addchar(pstream_t *p, char c)
+{
+ if (p->remain) {
+ *p->buffer++ = c;
+ --p->remain;
+ }
+ ++p->added;
+}
+
+int puts(const char *c)
+{
+ int n = 0;
+ while (c[n])
+ outb(0x3f8, c[n++]);
+ return n;
+}
+
+void print_str(pstream_t *p, const char *s, strprops_t props)
+{
+ const char *s_orig = s;
+ int npad = props.npad;
+
+ if (npad > 0) {
+ npad -= strlen(s_orig);
+ while (npad > 0) {
+ addchar(p, props.pad);
+ --npad;
+ }
+ }
+
+ while (*s)
+ addchar(p, *s++);
+
+ if (npad < 0) {
+ props.pad = ' '; /* ignore '0' flag with '-' flag */
+ npad += strlen(s_orig);
+ while (npad < 0) {
+ addchar(p, props.pad);
+ ++npad;
+ }
+ }
+}
+
+static char digits[16] = "0123456789abcdef";
+
+void print_int(pstream_t *ps, long n, int base, strprops_t props)
+{
+ char buf[sizeof(long) * 3 + 2], *p = buf;
+ int s = 0, i;
+
+ if (n < 0) {
+ n = -n;
+ s = 1;
+ }
+
+ while (n) {
+ *p++ = digits[n % base];
+ n /= base;
+ }
+
+ if (s)
+ *p++ = '-';
+
+ if (p == buf)
+ *p++ = '0';
+
+ for (i = 0; i < (p - buf) / 2; ++i) {
+ char tmp;
+
+ tmp = buf[i];
+ buf[i] = p[-1-i];
+ p[-1-i] = tmp;
+ }
+
+ *p = 0;
+
+ print_str(ps, buf, props);
+}
+
+void print_unsigned(pstream_t *ps, unsigned long n, int base,
+ strprops_t props)
+{
+ char buf[sizeof(long) * 3 + 1], *p = buf;
+ int i;
+
+ while (n) {
+ *p++ = digits[n % base];
+ n /= base;
+ }
+
+ if (p == buf)
+ *p++ = '0';
+
+ for (i = 0; i < (p - buf) / 2; ++i) {
+ char tmp;
+
+ tmp = buf[i];
+ buf[i] = p[-1-i];
+ p[-1-i] = tmp;
+ }
+
+ *p = 0;
+
+ print_str(ps, buf, props);
+}
+
+static int fmtnum(const char **fmt)
+{
+ const char *f = *fmt;
+ int len = 0, num;
+
+ if (*f == '-')
+ ++f, ++len;
+
+ while (*f >= '0' && *f <= '9')
+ ++f, ++len;
+
+ num = atol(*fmt);
+ *fmt += len;
+ return num;
+}
+
+int vsnprintf(char *buf, int size, const char *fmt, va_list va)
+{
+ pstream_t s;
+
+ s.buffer = buf;
+ s.remain = size - 1;
+ s.added = 0;
+ while (*fmt) {
+ char f = *fmt++;
+ int nlong = 0;
+ strprops_t props;
+ memset(&props, 0, sizeof(props));
+ props.pad = ' ';
+
+ if (f != '%') {
+ addchar(&s, f);
+ continue;
+ }
+ morefmt:
+ f = *fmt++;
+ do {
+ if (f == '%') {
+ addchar(&s, '%');
+ break;
+ }
+ if (f == 'c') {
+ addchar(&s, va_arg(va, int));
+ break;
+ }
+ if (f == '\0') {
+ --fmt;
+ break;
+ }
+ if (f == '0') {
+ props.pad = '0';
+ ++fmt;
+ /* fall through */
+ }
+ if ((f >= '1' && f <= '9') || f == '-') {
+ --fmt;
+ props.npad = fmtnum(&fmt);
+ goto morefmt;
+ }
+ if (f == 'l') {
+ ++nlong;
+ goto morefmt;
+ }
+ if (f == 'd') {
+ switch (nlong) {
+ case 0:
+ print_int(&s, va_arg(va, int), 10, props);
+ break;
+ case 1:
+ print_int(&s, va_arg(va, long), 10, props);
+ break;
+ default:
+ panic();
+ break;
+ }
+ break;
+ }
+ if (f == 'x') {
+ switch (nlong) {
+ case 0:
+ print_unsigned(&s, va_arg(va, unsigned), 16, props);
+ break;
+ case 1:
+ print_unsigned(&s, va_arg(va, unsigned long), 16, props);
+ break;
+ default:
+ panic();
+ break;
+ }
+ break;
+ }
+ if (f == 'p') {
+ print_str(&s, "0x", props);
+ print_unsigned(&s, (unsigned long)va_arg(va, void *), 16, props);
+ break;
+ }
+ if (f == 's') {
+ print_str(&s, va_arg(va, const char *), props);
+ break;
+ }
+ addchar(&s, f);
+ break;
+ } while(0);
+ }
+ *s.buffer = 0;
+ ++s.added;
+ return s.added;
+}
+
+
+int snprintf(char *buf, int size, const char *fmt, ...)
+{
+ va_list va;
+ int r;
+
+ va_start(va, fmt);
+ r = vsnprintf(buf, size, fmt, va);
+ va_end(va);
+ return r;
+}
+
+int printf(const char *fmt, ...)
+{
+ va_list va;
+ char buf[2000];
+ int r;
+
+ va_start(va, fmt);
+ r = vsnprintf(buf, sizeof buf, fmt, va);
+ va_end(va);
+ puts(buf);
+ return r;
+}
diff --git a/rom.ld.S b/rom.ld.S
deleted file mode 100644
index 04f2ff9..0000000
--- a/rom.ld.S
+++ /dev/null
@@ -1,19 +0,0 @@
-OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
-OUTPUT_ARCH(i386)
-
-SECTIONS {
- .text 0 : {
- *(.text)
- . = 0xfff0 ;
- *(.fixedaddr._fff0)
- . = 0x10000 ;
- }
-
- /DISCARD/ : {
- *(.debug*)
- *(.data)
- *(.bss)
- *(.eh_frame*)
- }
-}
-
diff --git a/string.c b/string.c
new file mode 100644
index 0000000..3029b9f
--- /dev/null
+++ b/string.c
@@ -0,0 +1,157 @@
+#include "string.h"
+
+unsigned long strlen(const char *buf)
+{
+ unsigned long len = 0;
+
+ while (*buf++)
+ ++len;
+ return len;
+}
+
+char *strcat(char *dest, const char *src)
+{
+ char *p = dest;
+
+ while (*p)
+ ++p;
+ while ((*p++ = *src++) != 0)
+ ;
+ return dest;
+}
+
+char *strcpy(char *dest, const char *src)
+{
+ *dest = 0;
+ return strcat(dest, src);
+}
+
+int strcmp(const char *a, const char *b)
+{
+ while (*a == *b) {
+ if (*a == '\0') {
+ break;
+ }
+ ++a, ++b;
+ }
+ return *a - *b;
+}
+
+char *strchr(const char *s, int c)
+{
+ while (*s != (char)c)
+ if (*s++ == '\0')
+ return NULL;
+ return (char *)s;
+}
+
+char *strstr(const char *s1, const char *s2)
+{
+ size_t l1, l2;
+
+ l2 = strlen(s2);
+ if (!l2)
+ return (char *)s1;
+ l1 = strlen(s1);
+ while (l1 >= l2) {
+ l1--;
+ if (!memcmp(s1, s2, l2))
+ return (char *)s1;
+ s1++;
+ }
+ return NULL;
+}
+
+void *memset(void *s, int c, size_t n)
+{
+ size_t i;
+ char *a = s;
+
+ for (i = 0; i < n; ++i)
+ a[i] = c;
+
+ return s;
+}
+
+void *memcpy(void *dest, const void *src, size_t n)
+{
+ size_t i;
+ char *a = dest;
+ const char *b = src;
+
+ for (i = 0; i < n; ++i)
+ a[i] = b[i];
+
+ return dest;
+}
+
+int memcmp(const void *s1, const void *s2, size_t n)
+{
+ const unsigned char *a = s1, *b = s2;
+ int ret = 0;
+
+ while (n--) {
+ ret = *a - *b;
+ if (ret)
+ break;
+ ++a, ++b;
+ }
+ return ret;
+}
+
+void *memmove(void *dest, const void *src, size_t n)
+{
+ const unsigned char *s = src;
+ unsigned char *d = dest;
+
+ if (d <= s) {
+ while (n--)
+ *d++ = *s++;
+ } else {
+ d += n, s += n;
+ while (n--)
+ *--d = *--s;
+ }
+ return dest;
+}
+
+void *memchr(const void *s, int c, size_t n)
+{
+ const unsigned char *str = s, chr = (unsigned char)c;
+
+ while (n--)
+ if (*str++ == chr)
+ return (void *)(str - 1);
+ return NULL;
+}
+
+long atol(const char *ptr)
+{
+ long acc = 0;
+ const char *s = ptr;
+ int neg, c;
+
+ while (*s == ' ' || *s == '\t')
+ s++;
+ if (*s == '-'){
+ neg = 1;
+ s++;
+ } else {
+ neg = 0;
+ if (*s == '+')
+ s++;
+ }
+
+ while (*s) {
+ if (*s < '0' || *s > '9')
+ break;
+ c = *s - '0';
+ acc = acc * 10 + c;
+ s++;
+ }
+
+ if (neg)
+ acc = -acc;
+
+ return acc;
+}
