---

asm.h

Go to the documentation of this file.

// See the end of this file for license information.

#ifndef TORSION_ASM_H
#define TORSION_ASM_H

// thank you, Linux kernel!
// all the functions/macros that we don't use currently are #if 0'd out

#define size_t unsigned int
#define NULL 0

// send a byte out to a port
inline void
outb(unsigned short int value, unsigned int port) {
  asm volatile("outb %%al, %%dx" : : "a" (value), "d" (port));
}

inline unsigned char
inb(unsigned int port) {
   unsigned char value;
   asm volatile("inb %%dx, %%al" : "=a" (value) : "d" (port));
   return value;
}

#if 0
static inline char * strcpy(char * dest,const char *src)
{
int d0, d1, d2;
__asm__ __volatile__(
        "1:\tlodsb\n\t"
        "stosb\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b"
        : "=&S" (d0), "=&D" (d1), "=&a" (d2)
        :"0" (src),"1" (dest) : "memory");
return dest;
}

static inline char * strncpy(char * dest,const char *src,size_t count)
{
int d0, d1, d2, d3;
__asm__ __volatile__(
        "1:\tdecl %2\n\t"
        "js 2f\n\t"
        "lodsb\n\t"
        "stosb\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b\n\t"
        "rep\n\t"
        "stosb\n"
        "2:"
        : "=&S" (d0), "=&D" (d1), "=&c" (d2), "=&a" (d3)
        :"0" (src),"1" (dest),"2" (count) : "memory");
return dest;
}

static inline char * strcat(char * dest,const char * src)
{
int d0, d1, d2, d3;
__asm__ __volatile__(
        "repne\n\t"
        "scasb\n\t"
        "decl %1\n"
        "1:\tlodsb\n\t"
        "stosb\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b"
        : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
        : "0" (src), "1" (dest), "2" (0), "3" (0xffffffff):"memory");
return dest;
}

static inline char * strncat(char * dest,const char * src,size_t count)
{
int d0, d1, d2, d3;
__asm__ __volatile__(
        "repne\n\t"
        "scasb\n\t"
        "decl %1\n\t"
        "movl %8,%3\n"
        "1:\tdecl %3\n\t"
        "js 2f\n\t"
        "lodsb\n\t"
        "stosb\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b\n"
        "2:\txorl %2,%2\n\t"
        "stosb"
        : "=&S" (d0), "=&D" (d1), "=&a" (d2), "=&c" (d3)
        : "0" (src),"1" (dest),"2" (0),"3" (0xffffffff), "g" (count)
        : "memory");
return dest;
}

static inline int strcmp(const char * cs,const char * ct)
{
int d0, d1;
register int __res;
__asm__ __volatile__(
        "1:\tlodsb\n\t"
        "scasb\n\t"
        "jne 2f\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b\n\t"
        "xorl %%eax,%%eax\n\t"
        "jmp 3f\n"
        "2:\tsbbl %%eax,%%eax\n\t"
        "orb $1,%%al\n"
        "3:"
        :"=a" (__res), "=&S" (d0), "=&D" (d1)
                     :"1" (cs),"2" (ct));
return __res;
}

static inline int strncmp(const char * cs,const char * ct,size_t count)
{
register int __res;
int d0, d1, d2;
__asm__ __volatile__(
        "1:\tdecl %3\n\t"
        "js 2f\n\t"
        "lodsb\n\t"
        "scasb\n\t"
        "jne 3f\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b\n"
        "2:\txorl %%eax,%%eax\n\t"
        "jmp 4f\n"
        "3:\tsbbl %%eax,%%eax\n\t"
        "orb $1,%%al\n"
        "4:"
                     :"=a" (__res), "=&S" (d0), "=&D" (d1), "=&c" (d2)
                     :"1" (cs),"2" (ct),"3" (count));
return __res;
}

static inline char * strchr(const char * s, int c)
{
int d0;
register char * __res;
__asm__ __volatile__(
        "movb %%al,%%ah\n"
        "1:\tlodsb\n\t"
        "cmpb %%ah,%%al\n\t"
        "je 2f\n\t"
        "testb %%al,%%al\n\t"
        "jne 1b\n\t"
        "movl $1,%1\n"
        "2:\tmovl %1,%0\n\t"
        "decl %0"
        :"=a" (__res), "=&S" (d0) : "1" (s),"0" (c));
return __res;
}

static inline char * strrchr(const char * s, int c)
{
int d0, d1;
register char * __res;
__asm__ __volatile__(
        "movb %%al,%%ah\n"
        "1:\tlodsb\n\t"
        "cmpb %%ah,%%al\n\t"
        "jne 2f\n\t"
        "leal -1(%%esi),%0\n"
        "2:\ttestb %%al,%%al\n\t"
        "jne 1b"
        :"=g" (__res), "=&S" (d0), "=&a" (d1) :"0" (0),"1" (s),"2" (c));
return __res;
}

static inline size_t strlen(const char * s)
{
int d0;
register int __res;
__asm__ __volatile__(
        "repne\n\t"
        "scasb\n\t"
        "notl %0\n\t"
        "decl %0"
        :"=c" (__res), "=&D" (d0) :"1" (s),"a" (0), "0" (0xffffffff));
return __res;
}
#endif

static inline void * __memcpy(void * to, const void * from, size_t n)
{
int d0, d1, d2;
__asm__ __volatile__(
        "rep ; movsl\n\t"
        "testb $2,%b4\n\t"
        "je 1f\n\t"
        "movsw\n"
        "1:\ttestb $1,%b4\n\t"
        "je 2f\n\t"
        "movsb\n"
        "2:"
        : "=&c" (d0), "=&D" (d1), "=&S" (d2)
        :"0" (n/4), "q" (n),"1" ((long) to),"2" ((long) from)
        : "memory");
return (to);
}

/*
 * This looks horribly ugly, but the compiler can optimize it totally,
 * as the count is constant.
 */
static inline void * __constant_memcpy(void * to, const void * from, size_t n)
{
        switch (n) {
                case 0:
                        return to;
                case 1:
                        *(unsigned char *)to = *(const unsigned char *)from;
                        return to;
                case 2:
                        *(unsigned short *)to = *(const unsigned short *)from;
                        return to;
                case 3:
                        *(unsigned short *)to = *(const unsigned short *)from;
                        *(2+(unsigned char *)to) = *(2+(const unsigned char *)from);
                        return to;
                case 4:
                        *(unsigned long *)to = *(const unsigned long *)from;
                        return to;
                case 6: /* for Ethernet addresses */
                        *(unsigned long *)to = *(const unsigned long *)from;
                        *(2+(unsigned short *)to) = *(2+(const unsigned short *)from);
                        return to;
                case 8:
                        *(unsigned long *)to = *(const unsigned long *)from;
                        *(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
                        return to;
                case 12:
                        *(unsigned long *)to = *(const unsigned long *)from;
                        *(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
                        *(2+(unsigned long *)to) = *(2+(const unsigned long *)from);
                        return to;
                case 16:
                        *(unsigned long *)to = *(const unsigned long *)from;
                        *(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
                        *(2+(unsigned long *)to) = *(2+(const unsigned long *)from);
                        *(3+(unsigned long *)to) = *(3+(const unsigned long *)from);
                        return to;
                case 20:
                        *(unsigned long *)to = *(const unsigned long *)from;
                        *(1+(unsigned long *)to) = *(1+(const unsigned long *)from);
                        *(2+(unsigned long *)to) = *(2+(const unsigned long *)from);
                        *(3+(unsigned long *)to) = *(3+(const unsigned long *)from);
                        *(4+(unsigned long *)to) = *(4+(const unsigned long *)from);
                        return to;
        }
#define COMMON(x) \
__asm__ __volatile__( \
        "rep ; movsl" \
        x \
        : "=&c" (d0), "=&D" (d1), "=&S" (d2) \
        : "0" (n/4),"1" ((long) to),"2" ((long) from) \
        : "memory");
{
        int d0, d1, d2;
        switch (n % 4) {
                case 0: COMMON(""); return to;
                case 1: COMMON("\n\tmovsb"); return to;
                case 2: COMMON("\n\tmovsw"); return to;
                default: COMMON("\n\tmovsw\n\tmovsb"); return to;
        }
}
  
#undef COMMON
}

#define memcpy(t, f, n) \
(__builtin_constant_p(n) ? \
 __constant_memcpy((t),(f),(n)) : \
 __memcpy((t),(f),(n)))

#if 0
/*
 * struct_cpy(x,y), copy structure *x into (matching structure) *y.
 *
 * We get link-time errors if the structure sizes do not match.
 * There is no runtime overhead, it's all optimized away at
 * compile time.
 */
extern void __struct_cpy_bug (void);

#define struct_cpy(x,y)                         \
({                                              \
        if (sizeof(*(x)) != sizeof(*(y)))       \
                __struct_cpy_bug;               \
        memcpy(x, y, sizeof(*(x)));             \
})
#endif

static inline void * memmove(void * dest,const void * src, size_t n)
{
int d0, d1, d2;
if (dest<src)
__asm__ __volatile__(
        "rep\n\t"
        "movsb"
        : "=&c" (d0), "=&S" (d1), "=&D" (d2)
        :"0" (n),"1" (src),"2" (dest)
        : "memory");
else
__asm__ __volatile__(
        "std\n\t"
        "rep\n\t"
        "movsb\n\t"
        "cld"
        : "=&c" (d0), "=&S" (d1), "=&D" (d2)
        :"0" (n),
         "1" (n-1+(const char *)src),
         "2" (n-1+(char *)dest)
        :"memory");
return dest;
}

#if 0
#define memcmp __builtin_memcmp

static inline void * memchr(const void * cs,int c,size_t count)
{
int d0;
register void * __res;
if (!count)
        return NULL;
__asm__ __volatile__(
        "repne\n\t"
        "scasb\n\t"
        "je 1f\n\t"
        "movl $1,%0\n"
        "1:\tdecl %0"
        :"=D" (__res), "=&c" (d0) : "a" (c),"0" (cs),"1" (count));
return __res;
}
#endif

static inline void * __memset_generic(void * s, char c,size_t count)
{
int d0, d1;
__asm__ __volatile__(
        "rep\n\t"
        "stosb"
        : "=&c" (d0), "=&D" (d1)
        :"a" (c),"1" (s),"0" (count)
        :"memory");
return s;
}

/* we might want to write optimized versions of these later */
#define __constant_count_memset(s,c,count) __memset_generic((s),(c),(count))

/*
 * memset(x,0,y) is a reasonably common thing to do, so we want to fill
 * things 32 bits at a time even when we don't know the size of the
 * area at compile-time..
 */
static inline void * __constant_c_memset(void * s, unsigned long c, size_t count)
{
int d0, d1;
__asm__ __volatile__(
        "rep ; stosl\n\t"
        "testb $2,%b3\n\t"
        "je 1f\n\t"
        "stosw\n"
        "1:\ttestb $1,%b3\n\t"
        "je 2f\n\t"
        "stosb\n"
        "2:"
        : "=&c" (d0), "=&D" (d1)
        :"a" (c), "q" (count), "0" (count/4), "1" ((long) s)
        :"memory");
return (s);     
}

#if 0
/* Added by Gertjan van Wingerde to make minix and sysv module work */
static inline size_t strnlen(const char * s, size_t count)
{
int d0;
register int __res;
__asm__ __volatile__(
        "movl %2,%0\n\t"
        "jmp 2f\n"
        "1:\tcmpb $0,(%0)\n\t"
        "je 3f\n\t"
        "incl %0\n"
        "2:\tdecl %1\n\t"
        "cmpl $-1,%1\n\t"
        "jne 1b\n"
        "3:\tsubl %2,%0"
        :"=a" (__res), "=&d" (d0)
        :"c" (s),"1" (count));
return __res;
}
/* end of additional stuff */

extern char *strstr(const char *cs, const char *ct);
#endif

/*
 * This looks horribly ugly, but the compiler can optimize it totally,
 * as we by now know that both pattern and count is constant..
 */
static inline void * __constant_c_and_count_memset(void * s, unsigned long pattern, size_t count)
{
        switch (count) {
                case 0:
                        return s;
                case 1:
                        *(unsigned char *)s = pattern;
                        return s;
                case 2:
                        *(unsigned short *)s = pattern;
                        return s;
                case 3:
                        *(unsigned short *)s = pattern;
                        *(2+(unsigned char *)s) = pattern;
                        return s;
                case 4:
                        *(unsigned long *)s = pattern;
                        return s;
        }
#define COMMON(x) \
__asm__  __volatile__( \
        "rep ; stosl" \
        x \
        : "=&c" (d0), "=&D" (d1) \
        : "a" (pattern),"0" (count/4),"1" ((long) s) \
        : "memory")
{
        int d0, d1;
        switch (count % 4) {
                case 0: COMMON(""); return s;
                case 1: COMMON("\n\tstosb"); return s;
                case 2: COMMON("\n\tstosw"); return s;
                default: COMMON("\n\tstosw\n\tstosb"); return s;
        }
}
  
#undef COMMON
}

#define __constant_c_x_memset(s, c, count) \
(__builtin_constant_p(count) ? \
 __constant_c_and_count_memset((s),(c),(count)) : \
 __constant_c_memset((s),(c),(count)))

#define __memset(s, c, count) \
(__builtin_constant_p(count) ? \
 __constant_count_memset((s),(c),(count)) : \
 __memset_generic((s),(c),(count)))

#define __HAVE_ARCH_MEMSET
#define memset(s, c, count) \
(__builtin_constant_p(c) ? \
 __constant_c_x_memset((s),(0x01010101UL*(unsigned char)(c)),(count)) : \
 __memset((s),(c),(count)))

#if 0
/*
 * find the first occurrence of byte 'c', or 1 past the area if none
 */
#define __HAVE_ARCH_MEMSCAN
static inline void * memscan(void * addr, int c, size_t size)
{
        if (!size)
                return addr;
        __asm__("repnz; scasb\n\t"
                "jnz 1f\n\t"
                "dec %%edi\n"
                "1:"
                : "=D" (addr), "=c" (size)
                : "0" (addr), "1" (size), "a" (c));
        return addr;
}
#endif

#endif

/* Torsion Operating System, Copyright (C) 2000-2002 Dan Helfman
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details (in the COPYING file).
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

---

Torsion Operating System, Copyright (C) 2000-2002 Dan Helfman