ref: 67a9174ff8425d3e4adec10b06664428f4aaf354
parent: 69b0980a42da16d97349ea962e57a5f55684e1a8
author: cinap_lenrek <[email protected]>
date: Sun Jun 26 11:28:01 EDT 2016
chacha: calculate rounds in separate function (helps registerizer), get rid of unrolled code
--- a/sys/src/libsec/port/chacha.c
+++ b/sys/src/libsec/port/chacha.c
@@ -15,13 +15,13 @@
};
/* little-endian data order */
-#define GET4(p) ((((((p)[3]<<8) | (p)[2])<<8) | (p)[1])<<8 | (p)[0])
-#define PUT4(p, v) (((p)[0]=v), (v>>=8), ((p)[1]=v), (v>>=8), ((p)[2]=v), (v>>=8), ((p)[3]=v))
+#define GET4(p) ((p)[0]|((p)[1]<<8)|((p)[2]<<16)|((p)[3]<<24))
+#define PUT4(p,v) (p)[0]=(v);(p)[1]=(v)>>8;(p)[2]=(v)>>16;(p)[3]=(v)>>24
#define ROTATE(v,c) ((u32int)((v) << (c)) | ((v) >> (32 - (c))))
#define QUARTERROUND(ia,ib,ic,id) { \- u32int a, b, c, d, t;\
+ u32int a, b, c, d, t; \
a = x[ia]; b = x[ib]; c = x[ic]; d = x[id]; \
a += b; t = d^a; d = ROTATE(t,16); \
c += d; t = b^c; b = ROTATE(t,12); \
@@ -95,12 +95,27 @@
}
static void
+dorounds(u32int x[Blockwords], int rounds)
+{+ for(; rounds > 0; rounds -= 2) {+ QUARTERROUND(0, 4, 8,12)
+ QUARTERROUND(1, 5, 9,13)
+ QUARTERROUND(2, 6,10,14)
+ QUARTERROUND(3, 7,11,15)
+
+ QUARTERROUND(0, 5,10,15)
+ QUARTERROUND(1, 6,11,12)
+ QUARTERROUND(2, 7, 8,13)
+ QUARTERROUND(3, 4, 9,14)
+ }
+}
+
+static void
encryptblock(Chachastate *s, uchar *src, uchar *dst)
{u32int x[Blockwords];
- int i, rounds;
+ int i;
- rounds = s->rounds;
x[0] = s->input[0];
x[1] = s->input[1];
x[2] = s->input[2];
@@ -117,37 +132,8 @@
x[13] = s->input[13];
x[14] = s->input[14];
x[15] = s->input[15];
+ dorounds(x, s->rounds);
- for(i = rounds; i > 0; i -= 2) {- QUARTERROUND(0, 4, 8,12)
- QUARTERROUND(1, 5, 9,13)
- QUARTERROUND(2, 6,10,14)
- QUARTERROUND(3, 7,11,15)
-
- QUARTERROUND(0, 5,10,15)
- QUARTERROUND(1, 6,11,12)
- QUARTERROUND(2, 7, 8,13)
- QUARTERROUND(3, 4, 9,14)
- }
-
-#ifdef FULL_UNROLL
- ENCRYPT(src+0*4, x[0], s->input[0], dst+0*4);
- ENCRYPT(src+1*4, x[1], s->input[1], dst+1*4);
- ENCRYPT(src+2*4, x[2], s->input[2], dst+2*4);
- ENCRYPT(src+3*4, x[3], s->input[3], dst+3*4);
- ENCRYPT(src+4*4, x[4], s->input[4], dst+4*4);
- ENCRYPT(src+5*4, x[5], s->input[5], dst+5*4);
- ENCRYPT(src+6*4, x[6], s->input[6], dst+6*4);
- ENCRYPT(src+7*4, x[7], s->input[7], dst+7*4);
- ENCRYPT(src+8*4, x[8], s->input[8], dst+8*4);
- ENCRYPT(src+9*4, x[9], s->input[9], dst+9*4);
- ENCRYPT(src+10*4, x[10], s->input[10], dst+10*4);
- ENCRYPT(src+11*4, x[11], s->input[11], dst+11*4);
- ENCRYPT(src+12*4, x[12], s->input[12], dst+12*4);
- ENCRYPT(src+13*4, x[13], s->input[13], dst+13*4);
- ENCRYPT(src+14*4, x[14], s->input[14], dst+14*4);
- ENCRYPT(src+15*4, x[15], s->input[15], dst+15*4);
-#else
for(i=0; i<nelem(x); i+=4){ENCRYPT(src, x[i], s->input[i], dst);
ENCRYPT(src+4, x[i+1], s->input[i+1], dst+4);
@@ -156,7 +142,6 @@
src += 16;
dst += 16;
}
-#endif
if(++s->input[12] == 0 && s->ivwords == 2)
s->input[13]++;