3 ms·
If adding more instructions negatively impacts efficiency, performance, cost and complexity, nobody would do it.
by flanked-evergl 2y ago
If adding more instructions negatively impacts efficiency, performance, cost and complexity, nobody would do it.
- foldr 2y agoProbably true now, but in ye olde days, some instructions existed primarily to make assembly programming more convenient. Assembly programming is a real pain in the RISCiest of RISC architectures, like SPARC. Here's an example from https://www.cs.clemson.edu/course/cpsc827/material/Code%20Generation/SPARC%20Reference%20Card.pdf https://www.cs.clemson.edu/course/cpsc827/material/Code%20Ge...: • All branches (including the one caused by CALL, below) take place after execution of the following instruction. • The position immediately after a branch is the “delay slot” and the instruction found there is the “delay instruction”. • If possible, place a useful instruction in the delay slot (one which can safely be done whether or not a conditional branch is taken). • If not, place a NOP in the delay slot. • Never place any other branch instruction in a delay slot. • Do not use SET in a delay slot (only half of it is really there).
- pjc50 2y agoDelay slots were such a hack. ARM never needed them.
- patmorgan23 2y agoOnly if decoder complexity/ efficiency is you bottleneck