Delete comment from: Ken Shirriff's blog

Mr Z said...

Wow... I guess I had forgotten that the 8085 didn't have a "jump if greater than" instruction like most of its contemporaries. I just went and looked at a couple 8085 instruction set summaries and sure enough, unless you include the undocumented instructions that test this flag, it's not there.

Other processors I've worked with from the time offer BGE/BLT that take (V xor S) to determine whether to branch, but they don't bother to store that as a discrete bit in the flags register. At least, the 6502, CP-1610 and 8086 take that approach.

Feb 13, 2013, 8:04:07 AM

Posted to Silicon reverse engineering: The 8085's undocumented flags