/*
 * x86_64 BIGNUM accelerator version 0.1, December 2002.
 *
 * Implemented by Andy Polyakov <appro@fy.chalmers.se> for the OpenSSL
 * project.
 *
 * Rights for redistribution and usage in source and binary forms are
 * granted according to the OpenSSL license. Warranty of any kind is
 * disclaimed.
 *
 * Q. Version 0.1? It doesn't sound like Andy, he used to assign real
 *    versions, like 1.0...
 * A. Well, that's because this code is basically a quick-n-dirty
 *    proof-of-concept hack. As you can see it's implemented with
 *    inline assembler, which means that you're bound to GCC and that
 *    there must be a room for fine-tuning.
 *
 * Q. Why inline assembler?
 * A. x86_64 features own ABI I'm not familiar with. Which is why
 *    I decided to let the compiler take care of subroutine
 *    prologue/epilogue as well as register allocation.
 *
 * Q. How much faster does it get?
 * A. Unfortunately people sitting on x86_64 hardware are prohibited
 *    to disclose the performance numbers, so they (SuSE labs to be
 *    specific) wouldn't tell me. However! Very similar coding technique
 *    (reaching out for 128-bit result from 64x64-bit multiplication)
 *    results in >3 times performance improvement on MIPS and I see no
 *    reason why gain on x86_64 would be so much different:-)
 */

#define BN_ULONG unsigned long

/*
 * "m"(a), "+m"(r)	is the way to favor DirectPath µ-code;
 * "g"(0)		let the compiler to decide where does it
 *			want to keep the value of zero;
 */
#define mul_add(r,a,word,carry) do {	\
	register BN_ULONG high,low;	\
	asm ("mulq %3"			\
		: "=a"(low),"=d"(high)	\
		: "a"(word),"m"(a)	\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(carry),"+d"(high)\
		: "a"(low),"g"(0)	\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+m"(r),"+d"(high)	\
		: "r"(carry),"g"(0)	\
		: "cc");		\
	carry=high;			\
	} while (0)

#define mul(r,a,word,carry) do {	\
	register BN_ULONG high,low;	\
	asm ("mulq %3"			\
		: "=a"(low),"=d"(high)	\
		: "a"(word),"g"(a)	\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(carry),"+d"(high)\
		: "a"(low),"g"(0)	\
		: "cc");		\
	(r)=carry, carry=high;		\
	} while (0)

#define sqr(r0,r1,a)			\
	asm ("mulq %2"			\
		: "=a"(r0),"=d"(r1)	\
		: "a"(a)		\
		: "cc");

BN_ULONG bn_mul_add_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
	{
	BN_ULONG c1=0;

	if (num <= 0) return(c1);

	while (num&~3)
		{
		mul_add(rp[0],ap[0],w,c1);
		mul_add(rp[1],ap[1],w,c1);
		mul_add(rp[2],ap[2],w,c1);
		mul_add(rp[3],ap[3],w,c1);
		ap+=4; rp+=4; num-=4;
		}
	if (num)
		{
		mul_add(rp[0],ap[0],w,c1); if (--num==0) return c1;
		mul_add(rp[1],ap[1],w,c1); if (--num==0) return c1;
		mul_add(rp[2],ap[2],w,c1); return c1;
		}
	
	return(c1);
	} 

BN_ULONG bn_mul_words(BN_ULONG *rp, BN_ULONG *ap, int num, BN_ULONG w)
	{
	BN_ULONG c1=0;

	if (num <= 0) return(c1);

	while (num&~3)
		{
		mul(rp[0],ap[0],w,c1);
		mul(rp[1],ap[1],w,c1);
		mul(rp[2],ap[2],w,c1);
		mul(rp[3],ap[3],w,c1);
		ap+=4; rp+=4; num-=4;
		}
	if (num)
		{
		mul(rp[0],ap[0],w,c1); if (--num == 0) return c1;
		mul(rp[1],ap[1],w,c1); if (--num == 0) return c1;
		mul(rp[2],ap[2],w,c1);
		}
	return(c1);
	} 

void bn_sqr_words(BN_ULONG *r, BN_ULONG *a, int n)
        {
	if (n <= 0) return;

	while (n&~3)
		{
		sqr(r[0],r[1],a[0]);
		sqr(r[2],r[3],a[1]);
		sqr(r[4],r[5],a[2]);
		sqr(r[6],r[7],a[3]);
		a+=4; r+=8; n-=4;
		}
	if (n)
		{
		sqr(r[0],r[1],a[0]); if (--n == 0) return;
		sqr(r[2],r[3],a[1]); if (--n == 0) return;
		sqr(r[4],r[5],a[2]);
		}
	}

BN_ULONG bn_div_words(BN_ULONG h, BN_ULONG l, BN_ULONG d)
{	BN_ULONG ret,waste;

	asm ("divq	%3"
		: "=a"(ret),"=d"(waste)
		: "a"(l),"d"(h),"g"(d)
		: "cc");

	return ret;
}

BN_ULONG bn_add_words (BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,int n)
{ BN_ULONG ret,i;

	if (n <= 0) return 0;

	asm (
	"	subq	%2,%2		\n"
	".align 16			\n"
	"1:	movq	(%4,%2,8),%0	\n"
	"	adcq	(%5,%2,8),%0	\n"
	"	movq	%0,(%3,%2,8)	\n"
	"	leaq	1(%2),%2	\n"
	"	loop	1b		\n"
	"	sbbq	%0,%0		\n"
		: "+a"(ret),"+c"(n),"+r"(i)
		: "r"(rp),"r"(ap),"r"(bp)
		: "cc"
	);

  return ret&1;
}

#ifndef SIMICS
BN_ULONG bn_sub_words (BN_ULONG *rp, BN_ULONG *ap, BN_ULONG *bp,int n)
{ BN_ULONG ret,i;

	if (n <= 0) return 0;

	asm (
	"	subq	%2,%2		\n"
	".align 16			\n"
	"1:	movq	(%4,%2,8),%0	\n"
	"	sbbq	(%5,%2,8),%0	\n"
	"	movq	%0,(%3,%2,8)	\n"
	"	leaq	1(%2),%2	\n"
	"	loop	1b		\n"
	"	sbbq	%0,%0		\n"
		: "+a"(ret),"+c"(n),"+r"(i)
		: "r"(rp),"r"(ap),"r"(bp)
		: "cc"
	);

  return ret&1;
}
#else
/* Simics 1.4<7 has buggy sbbq:-( */
#define BN_MASK2 0xffffffffffffffffL
BN_ULONG bn_sub_words(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n)
        {
	BN_ULONG t1,t2;
	int c=0;

	if (n <= 0) return((BN_ULONG)0);

	for (;;)
		{
		t1=a[0]; t2=b[0];
		r[0]=(t1-t2-c)&BN_MASK2;
		if (t1 != t2) c=(t1 < t2);
		if (--n <= 0) break;

		t1=a[1]; t2=b[1];
		r[1]=(t1-t2-c)&BN_MASK2;
		if (t1 != t2) c=(t1 < t2);
		if (--n <= 0) break;

		t1=a[2]; t2=b[2];
		r[2]=(t1-t2-c)&BN_MASK2;
		if (t1 != t2) c=(t1 < t2);
		if (--n <= 0) break;

		t1=a[3]; t2=b[3];
		r[3]=(t1-t2-c)&BN_MASK2;
		if (t1 != t2) c=(t1 < t2);
		if (--n <= 0) break;

		a+=4;
		b+=4;
		r+=4;
		}
	return(c);
	}
#endif

/* mul_add_c(a,b,c0,c1,c2)  -- c+=a*b for three word number c=(c2,c1,c0) */
/* mul_add_c2(a,b,c0,c1,c2) -- c+=2*a*b for three word number c=(c2,c1,c0) */
/* sqr_add_c(a,i,c0,c1,c2)  -- c+=a[i]^2 for three word number c=(c2,c1,c0) */
/* sqr_add_c2(a,i,c0,c1,c2) -- c+=2*a[i]*a[j] for three word number c=(c2,c1,c0) */

#if 0
/* original macros are kept for reference purposes */
#define mul_add_c(a,b,c0,c1,c2) {	\
	BN_ULONG ta=(a),tb=(b);		\
	t1 = ta * tb;			\
	t2 = BN_UMULT_HIGH(ta,tb);	\
	c0 += t1; t2 += (c0<t1)?1:0;	\
	c1 += t2; c2 += (c1<t2)?1:0;	\
	}

#define mul_add_c2(a,b,c0,c1,c2) {	\
	BN_ULONG ta=(a),tb=(b),t0;	\
	t1 = BN_UMULT_HIGH(ta,tb);	\
	t0 = ta * tb;			\
	t2 = t1+t1; c2 += (t2<t1)?1:0;	\
	t1 = t0+t0; t2 += (t1<t0)?1:0;	\
	c0 += t1; t2 += (c0<t1)?1:0;	\
	c1 += t2; c2 += (c1<t2)?1:0;	\
	}
#else
#define mul_add_c(a,b,c0,c1,c2)	do {	\
	asm ("mulq %3"			\
		: "=a"(t1),"=d"(t2)	\
		: "a"(a),"m"(b)		\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(c0),"+d"(t2)	\
		: "a"(t1),"g"(0)	\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(c1),"+r"(c2)	\
		: "d"(t2),"g"(0)	\
		: "cc");		\
	} while (0)

#define sqr_add_c(a,i,c0,c1,c2)	do {	\
	asm ("mulq %2"			\
		: "=a"(t1),"=d"(t2)	\
		: "a"(a[i])		\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(c0),"+d"(t2)	\
		: "a"(t1),"g"(0)	\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(c1),"+r"(c2)	\
		: "d"(t2),"g"(0)	\
		: "cc");		\
	} while (0)

#define mul_add_c2(a,b,c0,c1,c2) do {	\
	asm ("mulq %3"			\
		: "=a"(t1),"=d"(t2)	\
		: "a"(a),"m"(b)		\
		: "cc");		\
	asm ("addq %0,%0; adcq %2,%1"	\
		: "+d"(t2),"+r"(c2)	\
		: "g"(0)		\
		: "cc");		\
	asm ("addq %0,%0; adcq %2,%1"	\
		: "+a"(t1),"+d"(t2)	\
		: "g"(0)		\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(c0),"+d"(t2)	\
		: "a"(t1),"g"(0)	\
		: "cc");		\
	asm ("addq %2,%0; adcq %3,%1"	\
		: "+r"(c1),"+r"(c2)	\
		: "d"(t2),"g"(0)	\
		: "cc");		\
	} while (0)
#endif

#define sqr_add_c2(a,i,j,c0,c1,c2)	\
	mul_add_c2((a)[i],(a)[j],c0,c1,c2)

void bn_mul_comba8(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
	{
	BN_ULONG bl,bh;
	BN_ULONG t1,t2;
	BN_ULONG c1,c2,c3;

	c1=0;
	c2=0;
	c3=0;
	mul_add_c(a[0],b[0],c1,c2,c3);
	r[0]=c1;
	c1=0;
	mul_add_c(a[0],b[1],c2,c3,c1);
	mul_add_c(a[1],b[0],c2,c3,c1);
	r[1]=c2;
	c2=0;
	mul_add_c(a[2],b[0],c3,c1,c2);
	mul_add_c(a[1],b[1],c3,c1,c2);
	mul_add_c(a[0],b[2],c3,c1,c2);
	r[2]=c3;
	c3=0;
	mul_add_c(a[0],b[3],c1,c2,c3);
	mul_add_c(a[1],b[2],c1,c2,c3);
	mul_add_c(a[2],b[1],c1,c2,c3);
	mul_add_c(a[3],b[0],c1,c2,c3);
	r[3]=c1;
	c1=0;
	mul_add_c(a[4],b[0],c2,c3,c1);
	mul_add_c(a[3],b[1],c2,c3,c1);
	mul_add_c(a[2],b[2],c2,c3,c1);
	mul_add_c(a[1],b[3],c2,c3,c1);
	mul_add_c(a[0],b[4],c2,c3,c1);
	r[4]=c2;
	c2=0;
	mul_add_c(a[0],b[5],c3,c1,c2);
	mul_add_c(a[1],b[4],c3,c1,c2);
	mul_add_c(a[2],b[3],c3,c1,c2);
	mul_add_c(a[3],b[2],c3,c1,c2);
	mul_add_c(a[4],b[1],c3,c1,c2);
	mul_add_c(a[5],b[0],c3,c1,c2);
	r[5]=c3;
	c3=0;
	mul_add_c(a[6],b[0],c1,c2,c3);
	mul_add_c(a[5],b[1],c1,c2,c3);
	mul_add_c(a[4],b[2],c1,c2,c3);
	mul_add_c(a[3],b[3],c1,c2,c3);
	mul_add_c(a[2],b[4],c1,c2,c3);
	mul_add_c(a[1],b[5],c1,c2,c3);
	mul_add_c(a[0],b[6],c1,c2,c3);
	r[6]=c1;
	c1=0;
	mul_add_c(a[0],b[7],c2,c3,c1);
	mul_add_c(a[1],b[6],c2,c3,c1);
	mul_add_c(a[2],b[5],c2,c3,c1);
	mul_add_c(a[3],b[4],c2,c3,c1);
	mul_add_c(a[4],b[3],c2,c3,c1);
	mul_add_c(a[5],b[2],c2,c3,c1);
	mul_add_c(a[6],b[1],c2,c3,c1);
	mul_add_c(a[7],b[0],c2,c3,c1);
	r[7]=c2;
	c2=0;
	mul_add_c(a[7],b[1],c3,c1,c2);
	mul_add_c(a[6],b[2],c3,c1,c2);
	mul_add_c(a[5],b[3],c3,c1,c2);
	mul_add_c(a[4],b[4],c3,c1,c2);
	mul_add_c(a[3],b[5],c3,c1,c2);
	mul_add_c(a[2],b[6],c3,c1,c2);
	mul_add_c(a[1],b[7],c3,c1,c2);
	r[8]=c3;
	c3=0;
	mul_add_c(a[2],b[7],c1,c2,c3);
	mul_add_c(a[3],b[6],c1,c2,c3);
	mul_add_c(a[4],b[5],c1,c2,c3);
	mul_add_c(a[5],b[4],c1,c2,c3);
	mul_add_c(a[6],b[3],c1,c2,c3);
	mul_add_c(a[7],b[2],c1,c2,c3);
	r[9]=c1;
	c1=0;
	mul_add_c(a[7],b[3],c2,c3,c1);
	mul_add_c(a[6],b[4],c2,c3,c1);
	mul_add_c(a[5],b[5],c2,c3,c1);
	mul_add_c(a[4],b[6],c2,c3,c1);
	mul_add_c(a[3],b[7],c2,c3,c1);
	r[10]=c2;
	c2=0;
	mul_add_c(a[4],b[7],c3,c1,c2);
	mul_add_c(a[5],b[6],c3,c1,c2);
	mul_add_c(a[6],b[5],c3,c1,c2);
	mul_add_c(a[7],b[4],c3,c1,c2);
	r[11]=c3;
	c3=0;
	mul_add_c(a[7],b[5],c1,c2,c3);
	mul_add_c(a[6],b[6],c1,c2,c3);
	mul_add_c(a[5],b[7],c1,c2,c3);
	r[12]=c1;
	c1=0;
	mul_add_c(a[6],b[7],c2,c3,c1);
	mul_add_c(a[7],b[6],c2,c3,c1);
	r[13]=c2;
	c2=0;
	mul_add_c(a[7],b[7],c3,c1,c2);
	r[14]=c3;
	r[15]=c1;
	}

void bn_mul_comba4(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b)
	{
	BN_ULONG bl,bh;
	BN_ULONG t1,t2;
	BN_ULONG c1,c2,c3;

	c1=0;
	c2=0;
	c3=0;
	mul_add_c(a[0],b[0],c1,c2,c3);
	r[0]=c1;
	c1=0;
	mul_add_c(a[0],b[1],c2,c3,c1);
	mul_add_c(a[1],b[0],c2,c3,c1);
	r[1]=c2;
	c2=0;
	mul_add_c(a[2],b[0],c3,c1,c2);
	mul_add_c(a[1],b[1],c3,c1,c2);
	mul_add_c(a[0],b[2],c3,c1,c2);
	r[2]=c3;
	c3=0;
	mul_add_c(a[0],b[3],c1,c2,c3);
	mul_add_c(a[1],b[2],c1,c2,c3);
	mul_add_c(a[2],b[1],c1,c2,c3);
	mul_add_c(a[3],b[0],c1,c2,c3);
	r[3]=c1;
	c1=0;
	mul_add_c(a[3],b[1],c2,c3,c1);
	mul_add_c(a[2],b[2],c2,c3,c1);
	mul_add_c(a[1],b[3],c2,c3,c1);
	r[4]=c2;
	c2=0;
	mul_add_c(a[2],b[3],c3,c1,c2);
	mul_add_c(a[3],b[2],c3,c1,c2);
	r[5]=c3;
	c3=0;
	mul_add_c(a[3],b[3],c1,c2,c3);
	r[6]=c1;
	r[7]=c2;
	}

void bn_sqr_comba8(BN_ULONG *r, BN_ULONG *a)
	{
	BN_ULONG bl,bh;
	BN_ULONG t1,t2;
	BN_ULONG c1,c2,c3;

	c1=0;
	c2=0;
	c3=0;
	sqr_add_c(a,0,c1,c2,c3);
	r[0]=c1;
	c1=0;
	sqr_add_c2(a,1,0,c2,c3,c1);
	r[1]=c2;
	c2=0;
	sqr_add_c(a,1,c3,c1,c2);
	sqr_add_c2(a,2,0,c3,c1,c2);
	r[2]=c3;
	c3=0;
	sqr_add_c2(a,3,0,c1,c2,c3);
	sqr_add_c2(a,2,1,c1,c2,c3);
	r[3]=c1;
	c1=0;
	sqr_add_c(a,2,c2,c3,c1);
	sqr_add_c2(a,3,1,c2,c3,c1);
	sqr_add_c2(a,4,0,c2,c3,c1);
	r[4]=c2;
	c2=0;
	sqr_add_c2(a,5,0,c3,c1,c2);
	sqr_add_c2(a,4,1,c3,c1,c2);
	sqr_add_c2(a,3,2,c3,c1,c2);
	r[5]=c3;
	c3=0;
	sqr_add_c(a,3,c1,c2,c3);
	sqr_add_c2(a,4,2,c1,c2,c3);
	sqr_add_c2(a,5,1,c1,c2,c3);
	sqr_add_c2(a,6,0,c1,c2,c3);
	r[6]=c1;
	c1=0;
	sqr_add_c2(a,7,0,c2,c3,c1);
	sqr_add_c2(a,6,1,c2,c3,c1);
	sqr_add_c2(a,5,2,c2,c3,c1);
	sqr_add_c2(a,4,3,c2,c3,c1);
	r[7]=c2;
	c2=0;
	sqr_add_c(a,4,c3,c1,c2);
	sqr_add_c2(a,5,3,c3,c1,c2);
	sqr_add_c2(a,6,2,c3,c1,c2);
	sqr_add_c2(a,7,1,c3,c1,c2);
	r[8]=c3;
	c3=0;
	sqr_add_c2(a,7,2,c1,c2,c3);
	sqr_add_c2(a,6,3,c1,c2,c3);
	sqr_add_c2(a,5,4,c1,c2,c3);
	r[9]=c1;
	c1=0;
	sqr_add_c(a,5,c2,c3,c1);
	sqr_add_c2(a,6,4,c2,c3,c1);
	sqr_add_c2(a,7,3,c2,c3,c1);
	r[10]=c2;
	c2=0;
	sqr_add_c2(a,7,4,c3,c1,c2);
	sqr_add_c2(a,6,5,c3,c1,c2);
	r[11]=c3;
	c3=0;
	sqr_add_c(a,6,c1,c2,c3);
	sqr_add_c2(a,7,5,c1,c2,c3);
	r[12]=c1;
	c1=0;
	sqr_add_c2(a,7,6,c2,c3,c1);
	r[13]=c2;
	c2=0;
	sqr_add_c(a,7,c3,c1,c2);
	r[14]=c3;
	r[15]=c1;
	}

void bn_sqr_comba4(BN_ULONG *r, BN_ULONG *a)
	{
	BN_ULONG bl,bh;
	BN_ULONG t1,t2;
	BN_ULONG c1,c2,c3;

	c1=0;
	c2=0;
	c3=0;
	sqr_add_c(a,0,c1,c2,c3);
	r[0]=c1;
	c1=0;
	sqr_add_c2(a,1,0,c2,c3,c1);
	r[1]=c2;
	c2=0;
	sqr_add_c(a,1,c3,c1,c2);
	sqr_add_c2(a,2,0,c3,c1,c2);
	r[2]=c3;
	c3=0;
	sqr_add_c2(a,3,0,c1,c2,c3);
	sqr_add_c2(a,2,1,c1,c2,c3);
	r[3]=c1;
	c1=0;
	sqr_add_c(a,2,c2,c3,c1);
	sqr_add_c2(a,3,1,c2,c3,c1);
	r[4]=c2;
	c2=0;
	sqr_add_c2(a,3,2,c3,c1,c2);
	r[5]=c3;
	c3=0;
	sqr_add_c(a,3,c1,c2,c3);
	r[6]=c1;
	r[7]=c2;
	}