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Add missing shifts.

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This commit is contained in:
Thomas Harte 2024-02-27 09:55:24 -05:00
parent 4255283e33
commit 09c1b2d7db
1 changed files with 53 additions and 4 deletions
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57
OSBindings/Mac/Clock SignalTests/ARMDecoderTests.mm
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@ -26,12 +26,62 @@ void shift(uint32_t &source, uint32_t amount, uint32_t *carry = nullptr) {
} else if(amount == 32) { } else if(amount == 32) {
if constexpr (set_carry) *carry = source & 1; if constexpr (set_carry) *carry = source & 1;
source = 0; source = 0;
} else { } else if(amount > 0) {
if constexpr (set_carry) *carry = source & (0x8000'0000 >> amount); if constexpr (set_carry) *carry = source & (0x8000'0000 >> (amount - 1));
source <<= amount; source <<= amount;
} }
break; break;
case ShiftType::LogicalRight:
if(amount > 32) {
if constexpr (set_carry) *carry = 0;
source = 0;
} else if(amount == 32) {
if constexpr (set_carry) *carry = source & 0x8000'0000;
source = 0;
} else if(amount > 0) {
if constexpr (set_carry) *carry = source & (1 << (amount - 1));
source >>= amount;
} else {
// A logical shift right by '0' is treated as a shift by 32;
// assemblers are supposed to map LSR #0 to LSL #0.
if constexpr (set_carry) *carry = source & 0x8000'0000;
source = 0;
}
break;
case ShiftType::ArithmeticRight: {
const uint32_t sign = (source & 0x8000'0000) ? 0xffff'ffff : 0x0000'0000;
if(amount >= 32) {
if constexpr (set_carry) *carry = sign;
source = sign;
} else if(amount > 0) {
if constexpr (set_carry) *carry = source & (1 << (amount - 1));
source = (source >> amount) | (sign << (32 - amount));
} else {
// As per logical right, an arithmetic shift of '0' is
// treated as a shift by 32.
if constexpr (set_carry) *carry = source & 0x8000'0000;
source = sign;
}
} break;
case ShiftType::RotateRight: {
if(amount == 32) {
if constexpr (set_carry) *carry = source & 0x8000'0000;
} else if(amount == 0) {
// Rotate right by 0 is treated as a rotate right by 1 through carry.
const uint32_t high = *carry << 31;
if constexpr (set_carry) *carry = source & 1;
source = (source >> 1) | high;
} else {
amount &= 31;
if constexpr (set_carry) *carry = source & (1 << (amount - 1));
source = (source >> amount) | (source << (32 - amount));
}
} break;
default: break; default: break;
} }
} }
@ -54,7 +104,6 @@ void shift(ShiftType type, uint32_t &source, uint32_t amount, uint32_t *carry) {
} }
} }
struct Scheduler { struct Scheduler {
bool should_schedule(Condition condition) { bool should_schedule(Condition condition) {
return status.test(condition); return status.test(condition);
@ -67,7 +116,7 @@ struct Scheduler {
auto &destination = registers_[fields.destination()]; auto &destination = registers_[fields.destination()];
const uint32_t operand1 = registers_[fields.operand1()]; const uint32_t operand1 = registers_[fields.operand1()];
uint32_t operand2; uint32_t operand2;
uint32_t rotate_carry = 0; uint32_t rotate_carry = status.c();
// Populate carry from the shift only if it'll be used. // Populate carry from the shift only if it'll be used.
constexpr bool shift_sets_carry = is_logical(flags.operation()) && flags.set_condition_codes(); constexpr bool shift_sets_carry = is_logical(flags.operation()) && flags.set_condition_codes();