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Add TODO to self on undefined behaviour.

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This commit is contained in:
Thomas Harte 2022-10-17 23:14:14 -04:00
parent abb19e6670
commit fb2b7969a2
1 changed files with 7 additions and 0 deletions
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7
InstructionSets/M68k/Implementation/PerformImplementation.hpp
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@ -435,6 +435,13 @@ template <Operation operation, typename IntT, typename FlowController> void rox(
// When shift is zero, extend is unaffected but is copied to carry.
status.carry_flag = status.extend_flag;
} else {
// TODO: if the value of the right operand is negative or is greater or equal to
// the number of bits in the promoted left operand, the behavior is undefined.
//
// i.e. for a long if shift >= 32,
// or size + 1 - shift >= 32, i.e. 1 - shift >= 0, 1 >= shift; i.e. shift <= 1
// ... the code below is undefined behaviour.
switch(operation) {
case Operation::ROXLb: case Operation::ROXLw: case Operation::ROXLl:
status.carry_flag = Status::FlagT((destination >> (size - shift)) & 1);