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util/nvmutil: greatly optimise cmd_swap() 

instead of XOR-swapping every byte, have pointers to the
two parts and *XOR swap the pointers*. at the end of the
program execution, when writing, pwrite the two parts into
the same file
fsdg20230625
lbmkplaceholder 2022-12-23 08:41:18 +00:00
parent 7aafc62bf7
commit 6e5828e4a8
1 changed files with 18 additions and 9 deletions
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27
util/nvmutil/nvmutil.c
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@ -57,7 +57,7 @@ void writeGbeFile(int *fd, const char *filename);
#define SIZE_4KB 0x1000
#define SIZE_8KB 0x2000
uint8_t gbe[SIZE_8KB];
uint8_t *gbe = NULL, *gbe2 = NULL;
int part, gbeFileModified = 0;
uint8_t nvmPartModified[2];
@ -73,6 +73,10 @@ main(int argc, char *argv[])
char *strRMac = "??:??:??:??:??:??";
void (*cmd)(void) = NULL;
if ((gbe = (uint8_t *) malloc(SIZE_8KB)) == NULL)
err(errno, NULL);
gbe2 = gbe + SIZE_4KB;
nvmPartModified[0] = 0;
nvmPartModified[1] = 0;
@ -351,16 +355,18 @@ void
cmd_swap(void)
{
int part0, part1;
size_t g1 = (size_t) gbe;
size_t g2 = (size_t) gbe2;
part0 = validChecksum(0);
part1 = validChecksum(1);
if (part0 || part1) {
for(part0 = 0; part0 < SIZE_4KB; part0++) {
gbe[part0] ^= gbe[part1 = (part0 | SIZE_4KB)];
gbe[part1] ^= gbe[part0];
gbe[part0] ^= gbe[part1];
}
g1 ^= g2;
g2 ^= g1;
g1 ^= g2;
gbe = (uint8_t *) g1;
gbe2 = (uint8_t *) g2;
gbeFileModified = 1;
nvmPartModified[0] = 1;
@ -438,9 +444,12 @@ writeGbeFile(int *fd, const char *filename)
int partnum;
errno = 0;
if (pwrite((*fd), gbe, SIZE_8KB, 0) == SIZE_8KB)
if (close((*fd)))
err(errno, "%s", filename);
if (pwrite((*fd), gbe, SIZE_4KB, 0) != SIZE_4KB)
err(errno, "%s", filename);
if (pwrite((*fd), gbe2, SIZE_4KB, SIZE_4KB) != SIZE_4KB)
err(errno, "%s", filename);
if (close((*fd)))
err(errno, "%s", filename);
if (errno != 0)
return;