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To persuade myself in the future.
This commit is contained in:
Thomas Harte 2024-03-08 11:36:17 -05:00
parent 9406a97141
commit ca1c3dc005
1 changed files with 8 additions and 0 deletions
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8
InstructionSets/ARM/Registers.hpp
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@ -221,10 +221,15 @@ struct Registers {
// For outgoing modes other than FIQ, only save the final two registers for now; // For outgoing modes other than FIQ, only save the final two registers for now;
// if the incoming mode is FIQ then the other five will be saved in the next switch. // if the incoming mode is FIQ then the other five will be saved in the next switch.
// For FIQ, save all seven up front.
switch(mode_) { switch(mode_) {
// FIQ outgoing: save R8 to R14.
case Mode::FIQ: case Mode::FIQ:
std::copy(active_.begin() + 8, active_.begin() + 15, fiq_registers_.begin()); std::copy(active_.begin() + 8, active_.begin() + 15, fiq_registers_.begin());
break; break;
// Non-FIQ outgoing: save R13 and R14. If saving to the user registers,
// use only the final two slots.
case Mode::User: case Mode::User:
std::copy(active_.begin() + 13, active_.begin() + 15, user_registers_.begin() + 5); std::copy(active_.begin() + 13, active_.begin() + 15, user_registers_.begin() + 5);
break; break;
@ -240,7 +245,10 @@ struct Registers {
// For FIQ: save an additional five, then overwrite seven. // For FIQ: save an additional five, then overwrite seven.
switch(target_mode) { switch(target_mode) {
case Mode::FIQ: case Mode::FIQ:
// FIQ is incoming, so save registers 8 to 12 to the first five slots of the user registers.
std::copy(active_.begin() + 8, active_.begin() + 13, user_registers_.begin()); std::copy(active_.begin() + 8, active_.begin() + 13, user_registers_.begin());
// Replace R8 to R14.
std::copy(fiq_registers_.begin(), fiq_registers_.end(), active_.begin() + 8); std::copy(fiq_registers_.begin(), fiq_registers_.end(), active_.begin() + 8);
break; break;
case Mode::User: case Mode::User: