NetBSD-5.0.2/lib/libcrypto/arch/vax/bn_asm_vax.S
# $NetBSD: bn_asm_vax.S,v 1.2 2008/05/11 16:45:19 christos Exp $
#
# w.j.m. 15-jan-1999
#
# it's magic ...
#
# ULONG bn_mul_add_words(ULONG r[],ULONG a[],int n,ULONG w) {
# ULONG c = 0;
# int i;
# for(i = 0; i < n; i++) <c,r[i]> := r[i] + c + a[i] * w ;
# return c;
# }
.globl bn_mul_add_words
.type bn_mul_add_words@function
bn_mul_add_words:
.word 0x40
movl 4(%ap),%r2 # *r
movl 8(%ap),%r3 # *a
movl 12(%ap),%r4 # n
movl 16(%ap),%r5 # w
clrl %r6 # return value ("carry")
0: emul %r5,(%r3),(%r2),%r0 # w * a[0] + r[0] -> r0
# fixup for "negative" r[]
tstl (%r2)
bgeq 1f
incl %r1 # add 1 to highword
1: # add saved carry to result
addl2 %r6,%r0
adwc $0,%r1
# combined fixup for "negative" w, a[]
tstl %r5 # if w is negative...
bgeq 1f
addl2 (%r3),%r1 # ...add a[0] again to highword
1: tstl (%r3) # if a[0] is negative...
bgeq 1f
addl2 %r5,%r1 # ...add w again to highword
1:
movl %r0,(%r2)+ # save low word in dest & advance *r
addl2 $4,%r3 # advance *a
movl %r1,%r6 # high word in r6 for return value
sobgtr %r4,0b # loop?
movl %r6,%r0
ret
# .title vax_bn_mul_words unsigned multiply & add, 32*32+32=>64
#;
#; w.j.m. 15-jan-1999
#;
#; it's magic ...
#;
#; ULONG bn_mul_words(ULONG r[],ULONG a[],int n,ULONG w) {
#; ULONG c = 0;
#; int i;
#; for(i = 0; i < num; i++) <c,r[i]> := a[i] * w + c ;
#; return(c);
#; }
#
.globl bn_mul_words
.type bn_mul_words@function
bn_mul_words:
.word 0x40
movl 4(%ap),%r2 # *r
movl 8(%ap),%r3 # *a
movl 12(%ap),%r4 # n
movl 16(%ap),%r5 # w
clrl %r6 # carry
0: emul %r5,(%r3),%r6,%r0 # w * a[0] + carry -> r0
# fixup for "negative" carry
tstl %r6
bgeq 1f
incl %r1
1: # combined fixup for "negative" w, a[]
tstl %r5
bgeq 1f
addl2 (%r3),%r1
1: tstl (%r3)
bgeq 1f
addl2 %r5,%r1
1: movl %r0,(%r2)+
addl2 $4,%r3
movl %r1,%r6
sobgtr %r4,0b
movl %r6,%r0
ret
# .title vax_bn_sqr_words unsigned square, 32*32=>64
#;
#; w.j.m. 15-jan-1999
#;
#; it's magic ...
#;
#; void bn_sqr_words(ULONG r[],ULONG a[],int n) {
#; int i;
#; for(i = 0; i < n; i++) <r[2*i+1],r[2*i]> := a[i] * a[i] ;
#; }
#
.globl bn_sqr_words
.type bn_sqr_words@function
bn_sqr_words:
.word 0
movl 4(%ap),%r2 # r
movl 8(%ap),%r3 # a
movl 12(%ap),%r4 # n
0: movl (%r3)+,%r5 # r5 = a[] & advance
emul %r5,%r5,$0,%r0 # a[0] * a[0] + 0 -> r0
# fixup for "negative" a[]
tstl %r5
bgeq 1f
addl2 %r5,%r1
addl2 %r5,%r1
1: movq %r0,(%r2)+ # store 64-bit result
sobgtr %r4,0b # loop
ret
# .title vax_bn_div_words unsigned divide
#;
#; Richard Levitte 20-Nov-2000
#;
#; ULONG bn_div_words(ULONG h, ULONG l, ULONG d)
#; {
#; return ((ULONG)((((ULLONG)h)<<32)|l) / (ULLONG)d);
#; }
#;
#; Using EDIV would be very easy, if it didn't do signed calculations.
#; Any time any of the input numbers are signed, there are problems,
#; usually with integer overflow, at which point it returns useless
#; data (the quotient gets the value of l, and the remainder becomes 0).
#;
#; If it was just for the dividend, it would be very easy, just divide
#; it by 2 (unsigned), do the division, multiply the resulting quotient
#; and remainder by 2, add the bit that was dropped when dividing by 2
#; to the remainder, and do some adjustment so the remainder doesn't
#; end up larger than the divisor. For some cases when the divisor is
#; negative (from EDIV's point of view, i.e. when the highest bit is set),
#; dividing the dividend by 2 isn't enough, and since some operations
#; might generate integer overflows even when the dividend is divided by
#; 4 (when the high part of the shifted down dividend ends up being exactly
#; half of the divisor, the result is the quotient 0x80000000, which is
#; negative...) it needs to be divided by 8. Furthermore, the divisor needs
#; to be divided by 2 (unsigned) as well, to avoid more problems with the sign.
#; In this case, a little extra fiddling with the remainder is required.
#;
#; So, the simplest way to handle this is always to divide the dividend
#; by 8, and to divide the divisor by 2 if it's highest bit is set.
#; After EDIV has been used, the quotient gets multiplied by 8 if the
#; original divisor was positive, otherwise 4. The remainder, oddly
#; enough, is *always* multiplied by 8.
#; NOTE: in the case mentioned above, where the high part of the shifted
#; down dividend ends up being exactly half the shifted down divisor, we
#; end up with a 33 bit quotient. That's no problem however, it usually
#; means we have ended up with a too large remainder as well, and the
#; problem is fixed by the last part of the algorithm (next paragraph).
#;
#; The routine ends with comparing the resulting remainder with the
#; original divisor and if the remainder is larger, subtract the
#; original divisor from it, and increase the quotient by 1. This is
#; done until the remainder is smaller than the divisor.
#;
#; The complete algorithm looks like this:
#;
#; d' = d
#; l' = l & 7
#; [h,l] = [h,l] >> 3
#; [q,r] = floor([h,l] / d) # This is the EDIV operation
#; if (q < 0) q = -q # I doubt this is necessary any more
#;
#; r' = r >> 29
#; if (d' >= 0)
#; q' = q >> 29
#; q = q << 3
#; else
#; q' = q >> 30
#; q = q << 2
#; r = (r << 3) + l'
#;
#; if (d' < 0)
#; {
#; [r',r] = [r',r] - q
#; while ([r',r] < 0)
#; {
#; [r',r] = [r',r] + d
#; [q',q] = [q',q] - 1
#; }
#; }
#;
#; while ([r',r] >= d')
#; {
#; [r',r] = [r',r] - d'
#; [q',q] = [q',q] + 1
#; }
#;
#; return q
#
#;r2 = l, q
#;r3 = h, r
#;r4 = d
#;r5 = l'
#;r6 = r'
#;r7 = d'
#;r8 = q'
#
.globl bn_div_words
.type bn_div_words@function
bn_div_words:
.word 0x1c0
movl 4(%ap),%r3 # h
movl 8(%ap),%r2 # l
movl 12(%ap),%r4 # d
bicl3 $-8,%r2,%r5 # l' = l & 7
bicl3 $7,%r2,%r2
bicl3 $-8,%r3,%r6
bicl3 $7,%r3,%r3
addl2 %r6,%r2
rotl $-3,%r2,%r2 # l = l >> 3
rotl $-3,%r3,%r3 # h = h >> 3
movl %r4,%r7 # d' = d
clrl %r6 # r' = 0
clrl %r8 # q' = 0
tstl %r4
beql 0f # Uh-oh, the divisor is 0...
bgtr 1f
rotl $-1,%r4,%r4 # If d is negative, shift it right.
bicl2 $0x80000000,%r4 # Since d is then a large number, the
# lowest bit is insignificant
# (contradict that, and I'll fix the problem!)
1:
ediv %r4,%r2,%r2,%r3 # Do the actual division
tstl %r2
bgeq 1f
mnegl %r2,%r2 # if q < 0, negate it
1:
tstl %r7
blss 1f
rotl $3,%r2,%r2 # q = q << 3
bicl3 $-8,%r2,%r8 # q' gets the high bits from q
bicl3 $7,%r2,%r2
brb 2f
1: # else
rotl $2,%r2,%r2 # q = q << 2
bicl3 $-4,%r2,%r8 # q' gets the high bits from q
bicl3 $3,%r2,%r2
2:
rotl $3,%r3,%r3 # r = r << 3
bicl3 $-8,%r3,%r6 # r' gets the high bits from r
bicl3 $7,%r3,%r3
addl2 %r5,%r3 # r = r + l'
tstl %r7
bgeq 5f
bitl $1,%r7
beql 5f # if d' < 0 && d' & 1
subl2 %r2,%r3 # [r',r] = [r',r] - [q',q]
sbwc %r8,%r6
3:
bgeq 5f # while r < 0
decl %r2 # [q',q] = [q',q] - 1
sbwc $0,%r8
addl2 %r7,%r3 # [r',r] = [r',r] + d'
adwc $0,%r6
brb 3b
# The return points are placed in the middle to keep a short distance from
# all the branch points
1:
# movl %r3,%r1
movl %r2,%r0
ret
0:
movl $-1,%r0
ret
5:
tstl %r6
bneq 6f
cmpl %r3,%r7
blssu 1b # while [r',r] >= d'
6:
subl2 %r7,%r3 # [r',r] = [r',r] - d'
sbwc $0,%r6
incl %r2 # [q',q] = [q',q] + 1
adwc $0,%r8
brb 5b
# .title vax_bn_add_words unsigned add of two arrays
#;
#; Richard Levitte 20-Nov-2000
#;
#; ULONG bn_add_words(ULONG r[], ULONG a[], ULONG b[], int n) {
#; ULONG c = 0;
#; int i;
#; for (i = 0; i < n; i++) <c,r[i]> = a[i] + b[i] + c;
#; return(c);
#; }
#
.globl bn_add_words
.type bn_add_words@function
bn_add_words:
.word 0
movl 4(%ap),%r2 # r
movl 8(%ap),%r3 # a
movl 12(%ap),%r4 # b
movl 16(%ap),%r5 # n
clrl %r0
tstl %r5
bleq 1f
0: movl (%r3)+,%r1 # carry untouched
adwc (%r4)+,%r1 # carry used and touched
movl %r1,(%r2)+ # carry untouched
sobgtr %r5,0b # carry untouched
adwc $0,%r0
1: ret
#;
#; Richard Levitte 20-Nov-2000
#;
#; ULONG bn_sub_words(ULONG r[], ULONG a[], ULONG b[], int n) {
#; ULONG c = 0;
#; int i;
#; for (i = 0; i < n; i++) <c,r[i]> = a[i] - b[i] - c;
#; return(c);
#; }
#
.globl bn_sub_words
.type bn_sub_words@function
bn_sub_words:
.word 0x40
movl 4(%ap),%r2 # r
movl 8(%ap),%r3 # a
movl 12(%ap),%r4 # b
movl 16(%ap),%r5 # n
clrl %r0
tstl %r5
bleq 1f
0: movl (%r3)+,%r6 # carry untouched
sbwc (%r4)+,%r6 # carry used and touched
movl %r6,(%r2)+ # carry untouched
sobgtr %r5,0b # carry untouched
1: adwc $0,%r0
ret
#
# Ragge 20-Sep-2003
#
# Multiply a vector of 4/8 longword by another.
# Uses two loops and 16/64 emuls.
#
.globl bn_mul_comba4
.type bn_mul_comba4@function
bn_mul_comba4:
.word 0x3c0
movl $4,%r9 # 4*4
brb 6f
.globl bn_mul_comba8
.type bn_mul_comba8@function
bn_mul_comba8:
.word 0x3c0
movl $8,%r9 # 8*8
6: movl 8(%ap),%r3 # a[]
movl 12(%ap),%r7 # b[]
brb 5f
.globl bn_sqr_comba4
.type bn_sqr_comba4@function
bn_sqr_comba4:
.word 0x3c0
movl $4,%r9 # 4*4
brb 0f
.globl bn_sqr_comba8
.type bn_sqr_comba8@function
bn_sqr_comba8:
.word 0x3c0
movl $8,%r9 # 8*8
0:
movl 8(%ap),%r3 # a[]
movl %r3,%r7 # a[]
5: movl 4(%ap),%r5 # r[]
movl %r9,%r8
clrq (%r5) # clear destinatino, for add.
clrq 8(%r5)
clrq 16(%r5) # these only needed for comba8
clrq 24(%r5)
2: clrl %r4 # carry
movl %r9,%r6 # inner loop count
movl (%r7)+,%r2 # value to multiply with
1: emul %r2,(%r3),%r4,%r0
tstl %r4
bgeq 3f
incl %r1
3: tstl %r2
bgeq 3f
addl2 (%r3),%r1
3: tstl (%r3)
bgeq 3f
addl2 %r2,%r1
3: addl2 %r0,(%r5)+ # add to destination
adwc $0,%r1 # remember carry
movl %r1,%r4 # add carry in next emul
addl2 $4,%r3
sobgtr %r6,1b
movl %r4,(%r5) # save highest add result
ashl $2,%r9,%r4
subl2 %r4,%r3
subl2 $4,%r4
subl2 %r4,%r5
sobgtr %r8,2b
ret