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| author | Wan-Teh Chang <wtc@google.com> | 2015-10-05 14:55:55 -0700 |
|---|---|---|
| committer | Wan-Teh Chang <wtc@google.com> | 2015-10-05 14:55:55 -0700 |
| commit | f7de71911ffa9b76dd2ebb7dbf24910d0b1c9a0e (patch) | |
| tree | 76b1be2348f596e288c1b5a270915cf3425f56c5 /lib | |
| parent | 097da839383b2ac6fced2d797682b18b5360f4f4 (diff) | |
| download | nss-hg-f7de71911ffa9b76dd2ebb7dbf24910d0b1c9a0e.tar.gz | |
Bug 1180096: Add comments about the unaligned memory access, and add the
feature-test macro HAVE_UNALIGNED_ACCESS. r=twsmith,ryan.sleevi.
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/freebl/des.c | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/lib/freebl/des.c b/lib/freebl/des.c index 63a56acba..bcfcaba60 100644 --- a/lib/freebl/des.c +++ b/lib/freebl/des.c @@ -13,6 +13,13 @@ #include <stddef.h> /* for ptrdiff_t */ /* #define USE_INDEXING 1 */ +/* Some processors automatically fix up unaligned memory access, so they can + * read or write a HALF (4 bytes) at a time whether the address is 4-byte + * aligned or not. */ +#if defined(NSS_X86_OR_X64) +#define HAVE_UNALIGNED_ACCESS 1 +#endif + /* * The tables below are the 8 sbox functions, with the 6-bit input permutation * and the 32-bit output permutation pre-computed. @@ -421,11 +428,13 @@ DES_MakeSchedule( HALF * ks, const BYTE * key, DESDirection direction) int delta; unsigned int ls; -#if defined(NSS_X86_OR_X64) +#if defined(HAVE_UNALIGNED_ACCESS) left = HALFPTR(key)[0]; right = HALFPTR(key)[1]; +#if defined(IS_LITTLE_ENDIAN) BYTESWAP(left, temp); BYTESWAP(right, temp); +#endif #else if (((ptrdiff_t)key & 0x03) == 0) { left = HALFPTR(key)[0]; @@ -572,11 +581,13 @@ DES_Do1Block(HALF * ks, const BYTE * inbuf, BYTE * outbuf) register HALF left, right; register HALF temp; -#if defined(NSS_X86_OR_X64) +#if defined(HAVE_UNALIGNED_ACCESS) left = HALFPTR(inbuf)[0]; right = HALFPTR(inbuf)[1]; +#if defined(IS_LITTLE_ENDIAN) BYTESWAP(left, temp); BYTESWAP(right, temp); +#endif #else if (((ptrdiff_t)inbuf & 0x03) == 0) { left = HALFPTR(inbuf)[0]; @@ -643,9 +654,11 @@ DES_Do1Block(HALF * ks, const BYTE * inbuf, BYTE * outbuf) FP(left, right, temp); -#if defined(NSS_X86_OR_X64) +#if defined(HAVE_UNALIGNED_ACCESS) +#if defined(IS_LITTLE_ENDIAN) BYTESWAP(left, temp); BYTESWAP(right, temp); +#endif HALFPTR(outbuf)[0] = left; HALFPTR(outbuf)[1] = right; #else |