Commit 3f6b9d679621bfd88ce1e435dc265fa0a4d78c79
2013-10-27T00:27:39
Dramatically simplify the calculation of blockdiff.
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diff --git a/cgminer.c b/cgminer.c
index c93479f..8034880 100644
--- a/cgminer.c
+++ b/cgminer.c
@@ -4023,51 +4023,20 @@ static int block_sort(struct block *blocka, struct block *blockb)
return blocka->block_no - blockb->block_no;
}
+/* Decode the current block difficulty which is in packed form */
static void set_blockdiff(const struct work *work)
{
- uint64_t *data64, d64, diff64;
- double previous_diff;
- uint32_t diffhash[8];
- uint32_t difficulty;
- uint32_t diffbytes;
- uint32_t diffvalue;
- char rhash[32];
- int diffshift;
-
- difficulty = swab32(*((uint32_t *)(work->data + 72)));
-
- diffbytes = ((difficulty >> 24) & 0xff) - 3;
- diffvalue = difficulty & 0x00ffffff;
-
- diffshift = (diffbytes % 4) * 8;
- if (diffshift == 0) {
- diffshift = 32;
- diffbytes--;
- }
-
- memset(diffhash, 0, 32);
- diffbytes >>= 2;
- if (unlikely(diffbytes > 6))
- return;
- diffhash[diffbytes + 1] = diffvalue >> (32 - diffshift);
- diffhash[diffbytes] = diffvalue << diffshift;
-
- swab256(rhash, diffhash);
+ uint8_t pow = work->data[72];
+ int powdiff = (8 * (0x1d - 3)) - (8 * (pow - 3));
+ uint32_t diff32 = swab32(*((uint32_t *)(work->data + 72))) & 0x00FFFFFF;
+ double numerator = 0xFFFFULL << powdiff;
+ double ddiff = numerator / (double)diff32;
- if (opt_scrypt)
- data64 = (uint64_t *)(rhash + 2);
- else
- data64 = (uint64_t *)(rhash + 4);
- d64 = bswap_64(*data64);
- if (unlikely(!d64))
- d64 = 1;
-
- previous_diff = current_diff;
- diff64 = diffone / d64;
- suffix_string(diff64, block_diff, sizeof(block_diff), 0);
- current_diff = (double)diffone / (double)d64;
- if (unlikely(current_diff != previous_diff))
+ if (unlikely(current_diff != ddiff)) {
+ suffix_string(ddiff, block_diff, sizeof(block_diff), 0);
+ current_diff = ddiff;
applog(LOG_NOTICE, "Network diff set to %s", block_diff);
+ }
}
static bool test_work_current(struct work *work)