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Convert DIVU/DIVS logic to a template.

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This commit is contained in:
Thomas Harte 2022-10-11 16:16:53 -04:00
parent eb206a08d9
commit 28093196b9
1 changed files with 42 additions and 34 deletions
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76
InstructionSets/M68k/Implementation/PerformImplementation.hpp
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@ -184,6 +184,46 @@ void multiply(uint16_t source, uint32_t &destination, Status &status, FlowContro
}
}
template <bool is_divu, bool did_overflow, typename IntT, typename FlowController>
void did_divide(IntT dividend, IntT divisor, FlowController &flow_controller) {
if constexpr (is_divu) {
flow_controller.template did_divu<did_overflow>(dividend, divisor);
} else {
flow_controller.template did_divs<did_overflow>(dividend, divisor);
}
}
template <bool is_divu, typename Int16, typename Int32, typename FlowController>
void divide(uint16_t source, uint32_t &destination, Status &status, FlowController &flow_controller) {
status.carry_flag = 0;
const auto dividend = Int32(destination);
const auto divisor = Int32(Int16(source));
if(!divisor) {
status.negative_flag = status.overflow_flag = 0;
status.zero_result = 1;
flow_controller.raise_exception(Exception::IntegerDivideByZero);
did_divide<is_divu, false>(dividend, divisor, flow_controller);
return;
}
const auto quotient = int64_t(dividend) / int64_t(divisor);
if(quotient != Int32(Int16(quotient))) {
status.overflow_flag = 1;
did_divide<is_divu, true>(dividend, divisor, flow_controller);
return;
}
const auto remainder = Int16(dividend % divisor);
destination = uint32_t((uint32_t(remainder) << 16) | uint16_t(quotient));
status.overflow_flag = 0;
status.zero_result = Status::FlagT(quotient);
status.negative_flag = status.zero_result & 0x8000;
did_divide<is_divu, false>(dividend, divisor, flow_controller);
}
}
template <
@ -431,40 +471,8 @@ template <
Divisions.
*/
#define DIV(Type16, Type32, flow_function) { \
status.carry_flag = 0; \
\
const auto dividend = Type32(dest.l); \
const auto divisor = Type32(Type16(src.w)); \
\
if(!divisor) { \
status.negative_flag = status.overflow_flag = 0; \
status.zero_result = 1; \
flow_controller.raise_exception(Exception::IntegerDivideByZero); \
flow_controller.template flow_function<false>(dividend, divisor); \
return; \
} \
\
const auto quotient = int64_t(dividend) / int64_t(divisor); \
if(quotient != Type32(Type16(quotient))) { \
status.overflow_flag = 1; \
flow_controller.template flow_function<true>(dividend, divisor); \
return; \
} \
\
const auto remainder = Type16(dividend % divisor); \
dest.l = uint32_t((uint32_t(remainder) << 16) | uint16_t(quotient)); \
\
status.overflow_flag = 0; \
status.zero_result = Status::FlagT(quotient); \
status.negative_flag = status.zero_result & 0x8000; \
flow_controller.template flow_function<false>(dividend, divisor); \
}
case Operation::DIVU: DIV(uint16_t, uint32_t, did_divu); break;
case Operation::DIVS: DIV(int16_t, int32_t, did_divs); break;
#undef DIV
case Operation::DIVU: Primitive::divide<true, uint16_t, uint32_t>(src.w, dest.l, status, flow_controller); break;
case Operation::DIVS: Primitive::divide<false, int16_t, int32_t>(src.w, dest.l, status, flow_controller); break;
// TRAP, which is a nicer form of ILLEGAL.
case Operation::TRAP: