3 ms·
They have a special instruction now to predicate the next N instructions or not. In out of order implementations you want each instruction to have as few input
by Symmetry 10y ago
They have a special instruction now to predicate the next N instructions or not. In out of order implementations you want each instruction to have as few inputs as possible and my understanding was that the implicit input in the form of the branch information was causing problems. I've heard conflicting things about whether ARM processors split predicated instructions into two ops during decode.
- gpderetta 10y agoI'm way out of my depth as I know next to nothing about the ARM ISA, but as far as I know, there is no special instruction to predicate the next N instructions; conditional jumps don't count of course [1]. ARM v8 does have a predicated select instruction, but some form of it are available on many modern instruction sets. [1] interestingly, POWER8 is capable of converting unpredictable conditional jumps over a small number of instructions to conditional execution.