Fix carrying between bytes when saving and loading a checkpoint#118
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scribblemaniac wants to merge 1 commit intocathugger:masterfrom
Open
Fix carrying between bytes when saving and loading a checkpoint#118scribblemaniac wants to merge 1 commit intocathugger:masterfrom
scribblemaniac wants to merge 1 commit intocathugger:masterfrom
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The current logic for going between determseed and checkpoint is flawed. When it applies the checkpoint to determseed,
carry = 1only ifdetermseed[i] < checkpoint[i]. However, ifcheckpoint[i] = 0xFFand carry was already 1, thendetermseed[i] += 0xFF + 0x01and determseed[i] overflows to the same value. Since the value is the same, carry is set to false despite the fact that it did overflow. A similar issue affects the code going from determseed to checkpoint.There are multiple ways to fix this, but I think this solution is the most intuitive. This basically just does the math in 16-bit, using the bottom 8 bits for the result and the top 8 bits to determine the carry.
I don't believe this is a breaking change. Missing a carry when saving or loading a checkpoint will just result in some redundant work being performed. Using a deterministic seed should still find all the same matches.