diff options
Diffstat (limited to 'mu_instructions')
| -rw-r--r-- | mu_instructions | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/mu_instructions b/mu_instructions index 10d00f10..7a458660 100644 --- a/mu_instructions +++ b/mu_instructions @@ -293,6 +293,31 @@ Similar float variants like `break-if-float<` are aliases for the corresponding `addr` equivalents. The x86 instruction set stupidly has floating-point operations only update a subset of flags. +Four sets of conditional jumps are useful for detecting overflow. + +break-if-carry => "0f 82/jump-if-carry break/disp32" +break-if-carry label => "0f 82/jump-if-carry " label "/disp32" +loop-if-carry => "0f 82/jump-if-carry break/disp32" +loop-if-carry label => "0f 82/jump-if-carry " label "/disp32" + +break-if-not-carry => "0f 83/jump-if-not-carry break/disp32" +break-if-not-carry label => "0f 83/jump-if-not-carry " label "/disp32" +loop-if-not-carry => "0f 83/jump-if-not-carry break/disp32" +loop-if-not-carry label => "0f 83/jump-if-not-carry " label "/disp32" + +break-if-overflow => "0f 80/jump-if-overflow break/disp32" +break-if-overflow label => "0f 80/jump-if-overflow " label ":break/disp32" +loop-if-overflow => "0f 80/jump-if-overflow loop/disp32" +loop-if-overflow label => "0f 80/jump-if-overflow " label ":loop/disp32" + +break-if-not-overflow => "0f 81/jump-if-not-overflow break/disp32" +break-if-not-overflow label => "0f 81/jump-if-not-overflow " label ":break/disp32" +loop-if-not-overflow => "0f 81/jump-if-not-overflow loop/disp32" +loop-if-not-overflow label => "0f 81/jump-if-not-overflow " label ":loop/disp32" + +All this relies on a convention that every `{}` block is delimited by labels +ending in `:loop` and `:break`. + ## Returns The `return` instruction cleans up variable declarations just like an unconditional |