-rwxr-xr-x 6750 libntruprime-20241021/src/decode/PxQ/int16/decodegen.py raw
#!/usr/bin/env python3
import sys
from math import floor
Mlen = 761
if len(sys.argv) > 1: Mlen = int(sys.argv[1])
m0 = 4591
if len(sys.argv) > 2: m0 = int(sys.argv[2])
m1 = m0
if len(sys.argv) > 3: m1 = int(sys.argv[3])
# M is Mlen-1 copies of m0, plus 1 copy of m1
offset = m0//2
if len(sys.argv) > 4: offset = int(sys.argv[4])
div3 = False
if len(sys.argv) > 5: div3 = sys.argv[5]=='True'
top = 16384
print('/* auto-generated; do not edit */')
print('')
print('#include "crypto_decode.h"')
print('#include "crypto_int16.h"')
print('#include "crypto_int32.h"')
print('#define int16 crypto_int16')
print('#define int32 crypto_int32')
print("""
static int16 mullo(int16 x,int16 y)
{
return x*y;
}
static int16 mulhi(int16 x,int16 y)
{
return (x*(int32)y)>>16;
}
""")
print('void crypto_decode(void *v,const unsigned char *s)')
print('{')
print(' int16 *R = v;')
print(' long long i;')
print(' int16 a0,a1,ri,lo,s0,s1;')
def poke(layer,pos,contents):
if layer == 1 and div3:
return 'R[%s] = 3*%s%+d;' % (pos,contents,-offset)
if layer == 1 and offset != 0:
return 'R[%s] = %s%+d;' % (pos,contents,-offset)
return 'R[%s] = %s;' % (pos,contents)
def mulmoddata(c,q):
y = (c<<16)%q
if y*2 >= q: y -= q
t = 0
u = q
while not u&1:
t += 1
u >>= 1
uinv = pow(u,16383,65536)
if uinv>=32768: uinv -= 65536
assert (u*uinv)%65536 == 1
z = (y-(c<<16))>>t
z = (z*uinv)%65536
if z >= 32768: z -= 65536
assert (z*u-((y-(c<<16))>>t))%(2**16) == 0
return y,t,u,uinv,z
def inner(indent,inpos,m0,m1,bytes,outpos0,outpos1):
stanza = ''
y,t,u,uinv,z = mulmoddata(256,m0)
stanza += indent + 'ri = R[%s];\n' % (inpos)
a0lower,a0upper = 0,1<<14
for loop in reversed(range(bytes)):
stanza += indent + 's%d = *--s;\n' % loop
for loop in reversed(range(bytes)):
if y > 0:
a0lower,a0upper = a0lower*y,a0upper*y
else:
a0lower,a0upper = a0upper*y,a0lower*y
a0lower,a0upper = a0lower-(m0<<15),a0upper+(m0<<15)
a0lower,a0upper = a0lower>>16,a0upper>>16
if loop == bytes-1:
stanza += indent + 'lo = mullo(ri,%d);\n' % z
stanza += indent + 'a0 = mulhi(ri,%d)-mulhi(lo,%d); /* %d...%d */\n' % (y,m0,a0lower,a0upper)
else:
stanza += indent + 'lo = mullo(a0,%d);\n' % z
stanza += indent + 'a0 = mulhi(a0,%d)-mulhi(lo,%d); /* %d...%d */\n' % (y,m0,a0lower,a0upper)
a0upper += 255
stanza += indent + 'a0 += s%d; /* %d...%d */\n' % (loop,a0lower,a0upper)
if bytes == 0:
stanza += indent + 'a0 = ri;\n'
if a0upper >= 2*m0:
y1,t1,u1,uinv1,z1 = mulmoddata(1,m0)
if y1 > 0:
a0lower,a0upper = a0lower*y1,a0upper*y1
else:
a0lower,a0upper = a0upper*y1,a0lower*y1
a0lower,a0upper = a0lower-(m0<<15),a0upper+(m0<<15)
a0lower,a0upper = a0lower>>16,a0upper>>16
if bytes == 0:
stanza += indent + 'lo = mullo(a0,%d);\n' % z1
else:
stanza += indent + 'lo = mullo(a0,%d);\n' % z1
stanza += indent + 'a0 = mulhi(a0,%d)-mulhi(lo,%d); /* %d...%d */\n' % (y1,m0,a0lower,a0upper)
while a0upper >= m0:
a0lower,a0upper = a0lower-m0,a0upper-m0
stanza += indent + 'a0 -= %d; /* %d..>%d */\n' % (m0,a0lower,a0upper)
while a0lower < 0:
a0lower,a0upper = min(0,a0lower+m0),max(m0-1,a0upper)
stanza += indent + 'a0 += crypto_int16_negative_mask(a0)&%d; /* %d...%d */\n' % (m0,a0lower,a0upper)
if bytes == 0:
stanza += indent + 'a1 = (ri-a0)>>%d;\n' % t
elif bytes == 1:
if t == 0:
stanza += indent + 'a1 = (ri<<8)+s0-a0;\n'
elif t == 8:
stanza += indent + 'a1 = ri+((s0-a0)>>8);\n'
elif t < 8:
stanza += indent + 'a1 = (ri<<%d)+((s0-a0)>>%d);\n' % (8-t,t)
else:
stanza += indent + 'a1 = (ri+((s0-a0)>>8))>>%d;\n' % t-8
else:
assert bytes == 2
if t == 0:
stanza += indent + 'a1 = (s1<<8)+s0-a0;\n'
elif t == 8:
stanza += indent + 'a1 = (ri<<8)+s1+((s0-a0)>>8);\n'
elif t < 8:
stanza += indent + 'a1 = (ri<<%d)+(s1<<%d)+((s0-a0)>>%d);\n' % (16-t,8-t,t)
else:
stanza += indent + 'a1 = ((((int32)ri)<<16)+(s1<<8)+s0-a0)>>%d;\n' % t
stanza += indent + 'a1 = mullo(a1,%d);\n' % uinv
stanza += '\n'
stanza += indent + '/* invalid inputs might need reduction mod %d */\n' % m1
stanza += indent + 'a1 -= %d;\n' % m1
stanza += indent + 'a1 += crypto_int16_negative_mask(a1)&%d;\n' % m1
stanza += '\n'
stanza += indent + '%s\n' % poke(layer,outpos0,'a0')
stanza += indent + '%s\n' % poke(layer,outpos1,'a1')
return stanza
def stanzaloop(looplen,layer,m0,bytes):
stanza = ''
if looplen >= 1:
stanza += ' for (i = %d;i >= 0;--i) {\n' % (looplen-1)
stanza += inner(' ','i',m0,m0,bytes,'2*i','2*i+1')
stanza += ' }\n'
return stanza
stanzas = []
layer = 1
while Mlen > 1:
n0 = m0*m0
bytes0 = 0
while n0 >= top:
bytes0 += 1
n0 = (n0+255)>>8
if Mlen&1:
looplen = Mlen//2
r0 = 'R[%s]' % (looplen)
stanza = ' %s\n' % poke(layer,2*looplen,r0)
stanza += stanzaloop(looplen,layer,m0,bytes0)
n1 = m1
stanzas += [stanza]
else:
n1 = m0*m1
bytes1 = 0
while n1 >= top:
bytes1 += 1
n1 = (n1+255)>>8
if m1 == m0:
looplen = (Mlen+1)//2
stanza = stanzaloop(looplen,layer,m0,bytes0)
else:
looplen = (Mlen-1)//2
stanza = inner(' ',looplen,m0,m1,bytes1,2*looplen,2*looplen+1)
stanza += stanzaloop(looplen,layer,m0,bytes0)
stanzas += [stanza]
if m0 == m1:
stanzas += [' /* reconstruct mod %d*[%d] */\n' % (Mlen,m0)]
else:
stanzas += [' /* reconstruct mod %d*[%d]+[%d] */\n' % (Mlen-1,m0,m1)]
m0,m1,Mlen = n0,n1,(Mlen+1)//2
layer += 1
stanza = ''
stanza += ' s += crypto_decode_STRBYTES;\n'
stanza += ' a1 = 0;\n'
q = m1
y,t,u,uinv,z = mulmoddata(256,m1)
a1lower = 0
a1upper = 0
while m1 > 1:
if m1 != q:
stanza += ' lo = mullo(a1,%d);\n' % z
stanza += ' a1 = mulhi(a1,%d)-mulhi(lo,%d);\n' % (y,q)
if y > 0:
a1lower,a1upper = a1lower*y,a1upper*y
a1lower,a1upper = a1lower-(q<<15),a1upper+(q<<15)-1
else:
a1lower,a1upper = a1upper*y,a1lower*y
a1lower,a1upper = a1upper-(q<<15),a1lower+(q<<15)-1
a1lower >>= 16
a1upper >>= 16
a1upper += 255
stanza += ' a1 += *--s; /* %d...%d */\n' % (a1lower,a1upper)
m1 = (m1+255)>>8
while a1upper >= q:
a1lower,a1upper = a1lower-q,a1upper-q
stanza += ' a1 -= %d; /* %d...%d */\n' % (q,a1lower,a1upper)
while a1lower < 0:
a1lower,a1upper = min(0,a1lower+q),max(a1upper,q-1)
stanza += ' a1 += crypto_int16_negative_mask(a1)&%d; /* %d...%d */\n' % (q,a1lower,a1upper)
stanza += ' %s\n' % poke(layer,0,'a1')
stanzas += [stanza]
for stanza in reversed(stanzas):
print(' ')
sys.stdout.write(stanza)
print('}')