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Mildly reduce bit count weight; eliminate !!s.

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This commit is contained in:
Thomas Harte 2023-12-26 14:13:01 -05:00
parent 497ae935d6
commit 7b343b25cc
1 changed files with 8 additions and 3 deletions
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11
Components/DiskII/DiskII.cpp
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@ -61,7 +61,12 @@ void DiskII::set_control(Control control, bool on) {
if(stepper_mask_&2) direction += (((stepper_position_ - 2) + 4)&7) - 4; if(stepper_mask_&2) direction += (((stepper_position_ - 2) + 4)&7) - 4;
if(stepper_mask_&4) direction += (((stepper_position_ - 4) + 4)&7) - 4; if(stepper_mask_&4) direction += (((stepper_position_ - 4) + 4)&7) - 4;
if(stepper_mask_&8) direction += (((stepper_position_ - 6) + 4)&7) - 4; if(stepper_mask_&8) direction += (((stepper_position_ - 6) + 4)&7) - 4;
const int bits_set = (stepper_mask_&1) + ((stepper_mask_ >> 1)&1) + ((stepper_mask_ >> 2)&1) + ((stepper_mask_ >> 3)&1);
// TODO: when adopting C++20, replace with std::popcount.
int bits_set = stepper_mask_;
bits_set = (bits_set & 0x5) + ((bits_set >> 1) & 0x5);
bits_set = (bits_set & 0x3) + ((bits_set >> 2) & 0x3);
direction /= bits_set; direction /= bits_set;
// Compare to the stepper position to decide whether that pulls in the current cog notch, // Compare to the stepper position to decide whether that pulls in the current cog notch,
@ -126,7 +131,7 @@ void DiskII::run_for(const Cycles cycles) {
if(inputs_&input_mode) { if(inputs_&input_mode) {
// state_ & 0x80 should be the current level sent to the disk; // state_ & 0x80 should be the current level sent to the disk;
// therefore transitions in that bit should become flux transitions // therefore transitions in that bit should become flux transitions
drives_[active_drive_].write_bit(!!((state_ ^ address) & 0x80)); drives_[active_drive_].write_bit((state_ ^ address) & 0x80);
} }
// TODO: surely there's a less heavyweight solution than inline updates? // TODO: surely there's a less heavyweight solution than inline updates?
@ -179,7 +184,7 @@ void DiskII::decide_clocking_preference() {
} }
bool DiskII::is_write_protected() { bool DiskII::is_write_protected() {
return !!(stepper_mask_ & 2) | drives_[active_drive_].get_is_read_only(); return (stepper_mask_ & 2) || drives_[active_drive_].get_is_read_only();
} }
void DiskII::set_state_machine(const std::vector<uint8_t> &state_machine) { void DiskII::set_state_machine(const std::vector<uint8_t> &state_machine) {