diff options
| author | Leah Rowe <leah@libreboot.org> | 2023-06-01 07:21:30 +0100 |
|---|---|---|
| committer | Leah Rowe <leah@libreboot.org> | 2023-06-01 07:23:38 +0100 |
| commit | 7ab209d545c1dbe66c7305ffdab25bb03e57afa7 (patch) | |
| tree | 07b588ca7b676f227455dc16dc448a4ca4a81fca /util/nvmutil | |
| parent | 293ca0fcbb5b3cbf60c21f1a44241f7c11271513 (diff) | |
util/nvmutil: do xor swap in a macro
eventually, everything will be a macro!
Signed-off-by: Leah Rowe <leah@libreboot.org>
Diffstat (limited to 'util/nvmutil')
| -rw-r--r-- | util/nvmutil/nvmutil.c | 22 |
1 files changed, 8 insertions, 14 deletions
diff --git a/util/nvmutil/nvmutil.c b/util/nvmutil/nvmutil.c index c0873a25..9e821b10 100644 --- a/util/nvmutil/nvmutil.c +++ b/util/nvmutil/nvmutil.c @@ -53,7 +53,7 @@ void cmd_swap(void); void cmd_copy(void); int validChecksum(int partnum); void setWord(int pos16, int partnum, uint16_t val16); -void byteswap(int n, int partnum); +void xorswap_buf(int n, int partnum); void writeGbeFile(int *fd, const char *filename, size_t nw); void xpledge(const char *promises, const char *execpromises); void xunveil(const char *path, const char *permissions); @@ -68,6 +68,7 @@ void err_if(int condition); #define word(pos16, partnum) (buf16[pos16 + (partnum << 11)]) #define ERR() (errno = errno ? errno : ECANCELED) +#define xorswap(x, y) x ^= y, y ^= x, x ^= y uint16_t buf16[SIZE_4KB]; uint8_t *buf; @@ -166,7 +167,7 @@ readGbeFile(int *fd, const char *path, int flags, size_t nr) if (pread((*fd), (uint8_t *) gbe[p], nr, p << 12) == -1) err(ERR(), "%s", path); if (big_endian) - byteswap(nr, p); + xorswap_buf(nr, p); } } @@ -298,9 +299,7 @@ cmd_brick(void) void cmd_swap(void) { - gbe[0] ^= gbe[1]; /* speedhack: swap ptr, not words */ - gbe[1] ^= gbe[0]; - gbe[0] ^= gbe[1]; + xorswap(gbe[0], gbe[1]); /* speedhack: swap ptr, not words */ gbeFileModified = nvmPartModified[0] = nvmPartModified[1] = validChecksum(1) | validChecksum(0); } @@ -335,16 +334,11 @@ setWord(int pos16, int partnum, uint16_t val16) } void -byteswap(int n, int partnum) +xorswap_buf(int n, int partnum) { - int b1, b2, wcount = n >> 1; uint8_t *nbuf = (uint8_t *) gbe[partnum]; - for (int w = 0; w < wcount; w++) { - b1 = b2 = w << 1; - nbuf[b1] ^= nbuf[++b2]; /* xor swap */ - nbuf[b2] ^= nbuf[b1]; - nbuf[b1] ^= nbuf[b2]; - } + for (int w = 0; w < (n >> 1); w++) + xorswap(nbuf[w << 1], nbuf[(w << 1) + 1]); } void @@ -358,7 +352,7 @@ writeGbeFile(int *fd, const char *filename, size_t nw) if (!nvmPartModified[p]) goto next_part; if (big_endian) - byteswap(nw, p); + xorswap_buf(nw, p); if (pwrite((*fd), (uint8_t *) gbe[p], nw, p << 12) == -1) err(ERR(), "%s", filename); next_part: |