if the destination is more than 0x7F bytes away from the instruction following your Jcc, then use the long form.
But honestly, do you think that an extra 4-bytes really matter, if you consider the greatly added simplicity of *always* using the 6-byte instruction (0F 8x)?
If you start resizing instructions, then you have to make sure that *all* jumps that go beyond the resize/insertion point are also fixed. It's certainly not impossible, but seems like an overkill for what you want.
Last edited by doug; 09-13-2005 at 23:37.
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