Improve variable names
To some extent anyway.
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/aesni.c b/library/aesni.c
index 30b4b17..c52e63c 100644
--- a/library/aesni.c
+++ b/library/aesni.c
@@ -83,29 +83,29 @@
unsigned nr = ctx->nr; // Number of remaining rounds
// Load round key 0
- __m128i xmm0;
- memcpy(&xmm0, input, 16);
- xmm0 = _mm_xor_si128(xmm0, rk[0]); // xmm0 ^= *rk;
+ __m128i state;
+ memcpy(&state, input, 16);
+ state = _mm_xor_si128(state, rk[0]); // state ^= *rk;
++rk;
--nr;
if (mode == 0) {
while (nr != 0) {
- xmm0 = _mm_aesdec_si128(xmm0, *rk);
+ state = _mm_aesdec_si128(state, *rk);
++rk;
--nr;
}
- xmm0 = _mm_aesdeclast_si128(xmm0, *rk);
+ state = _mm_aesdeclast_si128(state, *rk);
} else {
while (nr != 0) {
- xmm0 = _mm_aesenc_si128(xmm0, *rk);
+ state = _mm_aesenc_si128(state, *rk);
++rk;
--nr;
}
- xmm0 = _mm_aesenclast_si128(xmm0, *rk);
+ state = _mm_aesenclast_si128(state, *rk);
}
- memcpy(output, &xmm0, 16);
+ memcpy(output, &state, 16);
return 0;
}
@@ -135,25 +135,23 @@
static void gcm_shift(__m128i *cc, __m128i *dd)
{
- /*
- * Now shift the result one bit to the left,
- * taking advantage of [CLMUL-WP] eq 27 (p. 18)
- */
- // // *cc = r1:r0
- // // *dd = r3:r2
- __m128i xmm1 = _mm_slli_epi64(*cc, 1); // r1<<1:r0<<1
- __m128i xmm2 = _mm_slli_epi64(*dd, 1); // r3<<1:r2<<1
- __m128i xmm3 = _mm_srli_epi64(*cc, 63); // r1>>63:r0>>63
- __m128i xmm4 = _mm_srli_epi64(*dd, 63); // r3>>63:r2>>63
- __m128i xmm5 = _mm_srli_si128(xmm3, 8); // 0:r1>>63
- xmm3 = _mm_slli_si128(xmm3, 8); // r0>>63:0
- xmm4 = _mm_slli_si128(xmm4, 8); // 0:r1>>63
+ /* [CMUCL-WP] Algorithm 5 Step 1: shift cc:dd one bit to the left,
+ * taking advantage of [CLMUL-WP] eq 27 (p. 18). */
+ // // *cc = r1:r0
+ // // *dd = r3:r2
+ __m128i cc_lo = _mm_slli_epi64(*cc, 1); // r1<<1:r0<<1
+ __m128i dd_lo = _mm_slli_epi64(*dd, 1); // r3<<1:r2<<1
+ __m128i cc_hi = _mm_srli_epi64(*cc, 63); // r1>>63:r0>>63
+ __m128i dd_hi = _mm_srli_epi64(*dd, 63); // r3>>63:r2>>63
+ __m128i xmm5 = _mm_srli_si128(cc_hi, 8); // 0:r1>>63
+ cc_hi = _mm_slli_si128(cc_hi, 8); // r0>>63:0
+ dd_hi = _mm_slli_si128(dd_hi, 8); // 0:r1>>63
- *cc = _mm_or_si128(xmm1, xmm3); // r1<<1|r0>>63:r0<<1
- *dd = _mm_or_si128(_mm_or_si128(xmm2, xmm4), xmm5); // r3<<1|r2>>62:r2<<1|r1>>63
+ *cc = _mm_or_si128(cc_lo, cc_hi); // r1<<1|r0>>63:r0<<1
+ *dd = _mm_or_si128(_mm_or_si128(dd_lo, dd_hi), xmm5); // r3<<1|r2>>62:r2<<1|r1>>63
}
-static __m128i gcm_reduce1(__m128i xx)
+static __m128i gcm_reduce(__m128i xx)
{
// // xx = x1:x0
/* [CLMUL-WP] Algorithm 5 Step 2 */
@@ -164,7 +162,7 @@
return _mm_xor_si128(dd, xx); // x1+a+b+c:x0 = d:x0
}
-static __m128i gcm_reduce2(__m128i dx)
+static __m128i gcm_mix(__m128i dx)
{
/* [CLMUL-WP] Algorithm 5 Steps 3 and 4 */
__m128i ee = _mm_srli_epi64(dx, 1); // e1:x0>>1 = e1:e0'
@@ -200,8 +198,8 @@
* using [CLMUL-WP] algorithm 5 (p. 18).
* Currently dd:cc holds x3:x2:x1:x0 (already shifted).
*/
- __m128i dx = gcm_reduce1(cc);
- __m128i xh = gcm_reduce2(dx);
+ __m128i dx = gcm_reduce(cc);
+ __m128i xh = gcm_mix(dx);
cc = _mm_xor_si128(xh, dd); // x3+h1:x2+h0
/* Now byte-reverse the outputs */
@@ -231,27 +229,27 @@
/*
* Key expansion, 128-bit case
*/
-static __m128i aesni_set_rk_128(__m128i xmm0, __m128i xmm1)
+static __m128i aesni_set_rk_128(__m128i state, __m128i xword)
{
/*
* Finish generating the next round key.
*
- * On entry xmm0 is r3:r2:r1:r0 and xmm1 is X:stuff:stuff:stuff
- * with X = rot( sub( r3 ) ) ^ RCON.
+ * On entry state is r3:r2:r1:r0 and xword is X:stuff:stuff:stuff
+ * with X = rot( sub( r3 ) ) ^ RCON (obtained with AESKEYGENASSIST).
*
- * On exit, xmm1 is r7:r6:r5:r4
+ * On exit, xword is r7:r6:r5:r4
* with r4 = X + r0, r5 = r4 + r1, r6 = r5 + r2, r7 = r6 + r3
* and this is returned, to be written to the round key buffer.
*/
- xmm1 = _mm_shuffle_epi32(xmm1, 0xff); // X:X:X:X
- xmm1 = _mm_xor_si128(xmm1, xmm0); // X+r3:X+r2:X+r1:r4
- xmm0 = _mm_slli_si128(xmm0, 4); // r2:r1:r0:0
- xmm1 = _mm_xor_si128(xmm1, xmm0); // X+r3+r2:X+r2+r1:r5:r4
- xmm0 = _mm_slli_si128(xmm0, 4); // r1:r0:0:0
- xmm1 = _mm_xor_si128(xmm1, xmm0); // X+r3+r2+r1:r6:r5:r4
- xmm0 = _mm_slli_si128(xmm0, 4); // r0:0:0:0
- xmm1 = _mm_xor_si128(xmm1, xmm0); // r7:r6:r5:r4
- return xmm1;
+ xword = _mm_shuffle_epi32(xword, 0xff); // X:X:X:X
+ xword = _mm_xor_si128(xword, state); // X+r3:X+r2:X+r1:r4
+ state = _mm_slli_si128(state, 4); // r2:r1:r0:0
+ xword = _mm_xor_si128(xword, state); // X+r3+r2:X+r2+r1:r5:r4
+ state = _mm_slli_si128(state, 4); // r1:r0:0:0
+ xword = _mm_xor_si128(xword, state); // X+r3+r2+r1:r6:r5:r4
+ state = _mm_slli_si128(state, 4); // r0:0:0:0
+ state = _mm_xor_si128(xword, state); // r7:r6:r5:r4
+ return state;
}
static void aesni_setkey_enc_128(unsigned char *rk_bytes,
@@ -275,39 +273,40 @@
/*
* Key expansion, 192-bit case
*/
-static void aesni_set_rk_192(__m128i *xmm0, __m128i *xmm1, __m128i xmm2,
+static void aesni_set_rk_192(__m128i *state0, __m128i *state1, __m128i xword,
unsigned char *rk)
{
/*
* Finish generating the next 6 quarter-keys.
*
- * On entry xmm0 is r3:r2:r1:r0, xmm1 is stuff:stuff:r5:r4
- * and xmm2 is stuff:stuff:X:stuff with X = rot( sub( r3 ) ) ^ RCON.
+ * On entry state0 is r3:r2:r1:r0, state1 is stuff:stuff:r5:r4
+ * and xword is stuff:stuff:X:stuff with X = rot( sub( r3 ) ) ^ RCON
+ * (obtained with AESKEYGENASSIST).
*
- * On exit, xmm0 is r9:r8:r7:r6 and xmm1 is stuff:stuff:r11:r10
+ * On exit, state0 is r9:r8:r7:r6 and state1 is stuff:stuff:r11:r10
* and those are written to the round key buffer.
*/
- xmm2 = _mm_shuffle_epi32(xmm2, 0x55); // X:X:X:X
- xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3:X+r2:X+r1:X+r0
- *xmm0 = _mm_slli_si128(*xmm0, 4); // r2:r1:r0:0
- xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3+r2:X+r2+r1:X+r1+r0:X+r0
- *xmm0 = _mm_slli_si128(*xmm0, 4); // r1:r0:0:0
- xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3+r2+r1:X+r2+r1+r0:X+r1+r0:X+r0
- *xmm0 = _mm_slli_si128(*xmm0, 4); // r0:0:0:0
- xmm2 = _mm_xor_si128(xmm2, *xmm0); // X+r3+r2+r1+r0:X+r2+r1+r0:X+r1+r0:X+r0
- *xmm0 = xmm2; // = r9:r8:r7:r6
+ xword = _mm_shuffle_epi32(xword, 0x55); // X:X:X:X
+ xword = _mm_xor_si128(xword, *state0); // X+r3:X+r2:X+r1:X+r0
+ *state0 = _mm_slli_si128(*state0, 4); // r2:r1:r0:0
+ xword = _mm_xor_si128(xword, *state0); // X+r3+r2:X+r2+r1:X+r1+r0:X+r0
+ *state0 = _mm_slli_si128(*state0, 4); // r1:r0:0:0
+ xword = _mm_xor_si128(xword, *state0); // X+r3+r2+r1:X+r2+r1+r0:X+r1+r0:X+r0
+ *state0 = _mm_slli_si128(*state0, 4); // r0:0:0:0
+ xword = _mm_xor_si128(xword, *state0); // X+r3+r2+r1+r0:X+r2+r1+r0:X+r1+r0:X+r0
+ *state0 = xword; // = r9:r8:r7:r6
- xmm2 = _mm_shuffle_epi32(xmm2, 0xff); // r9:r9:r9:r9
- xmm2 = _mm_xor_si128(xmm2, *xmm1); // stuff:stuff:r9+r5:r9+r4
- *xmm1 = _mm_slli_si128(*xmm1, 4); // stuff:stuff:r4:0
- xmm2 = _mm_xor_si128(xmm2, *xmm1); // stuff:stuff:r9+r5+r4:r9+r4
- *xmm1 = xmm2; // = stuff:stuff:r11:r10
+ xword = _mm_shuffle_epi32(xword, 0xff); // r9:r9:r9:r9
+ xword = _mm_xor_si128(xword, *state1); // stuff:stuff:r9+r5:r9+r4
+ *state1 = _mm_slli_si128(*state1, 4); // stuff:stuff:r4:0
+ xword = _mm_xor_si128(xword, *state1); // stuff:stuff:r9+r5+r4:r9+r4
+ *state1 = xword; // = stuff:stuff:r11:r10
- /* Store xmm0 and the low half of xmm1 into rk, which is conceptually
+ /* Store state0 and the low half of state1 into rk, which is conceptually
* an array of 24-byte elements. Since 24 is not a multiple of 16,
- * rk is not necessarily aligned so just `*rk = *xmm0` doesn't work. */
- memcpy(rk, xmm0, 16);
- _mm_storeu_si64(rk + 16, *xmm1);
+ * rk is not necessarily aligned so just `*rk = *state0` doesn't work. */
+ memcpy(rk, state0, 16);
+ _mm_storeu_si64(rk + 16, *state1);
}
static void aesni_setkey_enc_192(unsigned char *rk,
@@ -316,55 +315,56 @@
/* First round: use original key */
memcpy(rk, key, 24);
/* aes.c guarantees that rk is aligned on a 16-byte boundary. */
- __m128i xmm0 = ((__m128i *) rk)[0];
- __m128i xmm1 = _mm_loadl_epi64(((__m128i *) rk) + 1);
+ __m128i state0 = ((__m128i *) rk)[0];
+ __m128i state1 = _mm_loadl_epi64(((__m128i *) rk) + 1);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x01), rk + 24 * 1);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x02), rk + 24 * 2);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x04), rk + 24 * 3);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x08), rk + 24 * 4);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x10), rk + 24 * 5);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x20), rk + 24 * 6);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x40), rk + 24 * 7);
- aesni_set_rk_192(&xmm0, &xmm1, _mm_aeskeygenassist_si128(xmm1, 0x80), rk + 24 * 8);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x01), rk + 24 * 1);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x02), rk + 24 * 2);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x04), rk + 24 * 3);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x08), rk + 24 * 4);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x10), rk + 24 * 5);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x20), rk + 24 * 6);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x40), rk + 24 * 7);
+ aesni_set_rk_192(&state0, &state1, _mm_aeskeygenassist_si128(state1, 0x80), rk + 24 * 8);
}
/*
* Key expansion, 256-bit case
*/
-static void aesni_set_rk_256(__m128i xmm0, __m128i xmm1, __m128i xmm2,
+static void aesni_set_rk_256(__m128i state0, __m128i state1, __m128i xword,
__m128i *rk0, __m128i *rk1)
{
/*
* Finish generating the next two round keys.
*
- * On entry xmm0 is r3:r2:r1:r0, xmm1 is r7:r6:r5:r4 and
- * xmm2 is X:stuff:stuff:stuff with X = rot( sub( r7 )) ^ RCON
+ * On entry state0 is r3:r2:r1:r0, state1 is r7:r6:r5:r4 and
+ * xword is X:stuff:stuff:stuff with X = rot( sub( r7 )) ^ RCON
+ * (obtained with AESKEYGENASSIST).
*
* On exit, *rk0 is r11:r10:r9:r8 and *rk1 is r15:r14:r13:r12
*/
- xmm2 = _mm_shuffle_epi32(xmm2, 0xff);
- xmm2 = _mm_xor_si128(xmm2, xmm0);
- xmm0 = _mm_slli_si128(xmm0, 4);
- xmm2 = _mm_xor_si128(xmm2, xmm0);
- xmm0 = _mm_slli_si128(xmm0, 4);
- xmm2 = _mm_xor_si128(xmm2, xmm0);
- xmm0 = _mm_slli_si128(xmm0, 4);
- xmm0 = _mm_xor_si128(xmm0, xmm2);
- *rk0 = xmm0;
+ xword = _mm_shuffle_epi32(xword, 0xff);
+ xword = _mm_xor_si128(xword, state0);
+ state0 = _mm_slli_si128(state0, 4);
+ xword = _mm_xor_si128(xword, state0);
+ state0 = _mm_slli_si128(state0, 4);
+ xword = _mm_xor_si128(xword, state0);
+ state0 = _mm_slli_si128(state0, 4);
+ state0 = _mm_xor_si128(state0, xword);
+ *rk0 = state0;
- /* Set xmm2 to stuff:Y:stuff:stuff with Y = subword( r11 )
+ /* Set xword to stuff:Y:stuff:stuff with Y = subword( r11 )
* and proceed to generate next round key from there */
- xmm2 = _mm_aeskeygenassist_si128(xmm0, 0x00);
- xmm2 = _mm_shuffle_epi32(xmm2, 0xaa);
- xmm2 = _mm_xor_si128(xmm2, xmm1);
- xmm1 = _mm_slli_si128(xmm1, 4);
- xmm2 = _mm_xor_si128(xmm2, xmm1);
- xmm1 = _mm_slli_si128(xmm1, 4);
- xmm2 = _mm_xor_si128(xmm2, xmm1);
- xmm1 = _mm_slli_si128(xmm1, 4);
- xmm1 = _mm_xor_si128(xmm1, xmm2);
- *rk1 = xmm1;
+ xword = _mm_aeskeygenassist_si128(state0, 0x00);
+ xword = _mm_shuffle_epi32(xword, 0xaa);
+ xword = _mm_xor_si128(xword, state1);
+ state1 = _mm_slli_si128(state1, 4);
+ xword = _mm_xor_si128(xword, state1);
+ state1 = _mm_slli_si128(state1, 4);
+ xword = _mm_xor_si128(xword, state1);
+ state1 = _mm_slli_si128(state1, 4);
+ state1 = _mm_xor_si128(state1, xword);
+ *rk1 = state1;
}
static void aesni_setkey_enc_256(unsigned char *rk_bytes,