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Collapse [A/L]S[L/R].[bwl] into a template.
This commit is contained in:
Thomas Harte
parent
d5ceb934d2
commit
47e8f3c0f1
@ -251,6 +251,74 @@ template <typename IntT> void set_neg_zero(IntT result, Status &status) {
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status.negative_flag = result & top_bit<IntT>();
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}
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/// Perform an arithmetic or logical shift, i.e. any of LSL, LSR, ASL or ASR.
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template <Operation operation, typename IntT, typename FlowController> void shift(uint32_t source, IntT &destination, Status &status, FlowController &flow_controller) {
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static_assert(
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operation == Operation::ASLb || operation == Operation::ASLw || operation == Operation::ASLl ||
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operation == Operation::ASRb || operation == Operation::ASRw || operation == Operation::ASRl ||
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operation == Operation::LSLb || operation == Operation::LSLw || operation == Operation::LSLl ||
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operation == Operation::LSRb || operation == Operation::LSRw || operation == Operation::LSRl
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);
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const auto size = bit_size<IntT>();
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const auto shift = shift_count<IntT>(uint8_t(source), flow_controller);
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if(!shift) {
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status.carry_flag = status.overflow_flag = 0;
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} else {
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enum class Type {
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ASL, LSL, ASR, LSR
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} type;
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switch(operation) {
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case Operation::ASLb: case Operation::ASLw: case Operation::ASLl:
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type = Type::ASL;
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break;
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case Operation::LSLb: case Operation::LSLw: case Operation::LSLl:
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type = Type::LSL;
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break;
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case Operation::ASRb: case Operation::ASRw: case Operation::ASRl:
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type = Type::ASR;
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break;
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case Operation::LSRb: case Operation::LSRw: case Operation::LSRl:
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type = Type::LSR;
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break;
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}
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switch(type) {
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case Type::ASL:
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case Type::LSL:
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status.overflow_flag =
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type == Type::LSL ?
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0 : (destination ^ (destination << shift)) & top_bit<IntT>();
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if(shift < size) {
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status.carry_flag = status.extend_flag = (destination >> (size - shift)) & 1;
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} else {
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status.carry_flag = status.extend_flag = 0;
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}
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destination <<= shift;
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break;
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case Type::ASR:
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case Type::LSR: {
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const IntT sign_word =
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type == Type::LSR ?
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0 : (destination & top_bit<IntT>() ? IntT(~0) : 0);
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status.overflow_flag = 0;
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status.carry_flag = status.extend_flag = (destination >> (shift - 1)) & 1;
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if(shift < size) {
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destination = IntT((destination >> shift) | (sign_word << (size - shift)));
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} else {
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destination = sign_word;
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}
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} break;
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}
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}
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set_neg_zero(destination, status);
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}
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/// Perform a rotate without extend, i.e. any of RO[L/R].[b/w/l].
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template <Operation operation, typename IntT, typename FlowController> void rotate(uint32_t source, IntT &destination, Status &status, FlowController &flow_controller) {
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static_assert(
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@ -770,79 +838,6 @@ template <
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set_neg_zero(v, m); \
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status.overflow_flag = (Status::FlagT(value) ^ status.zero_result) & Status::FlagT(m);
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#define decode_shift_count(type) \
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int shift_count = src.l & 63; \
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flow_controller.template did_shift<type>(shift_count);
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#define set_flags_w(t) set_flags(src.w, 0x8000, t)
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#define asl(destination, size) {\
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decode_shift_count(decltype(destination)); \
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const auto value = destination; \
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\
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if(!shift_count) { \
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status.carry_flag = status.overflow_flag = 0; \
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} else { \
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destination = (shift_count < size) ? decltype(destination)(value << shift_count) : 0; \
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status.extend_flag = status.carry_flag = Status::FlagT(value) & Status::FlagT( (1u << (size - 1)) >> (shift_count - 1) ); \
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\
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if(shift_count >= size) status.overflow_flag = value && (value != decltype(value)(-1)); \
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else { \
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const auto mask = decltype(destination)(0xffffffff << (size - shift_count)); \
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status.overflow_flag = mask & value && ((mask & value) != mask); \
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} \
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} \
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\
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set_neg_zero(destination, 1 << (size - 1)); \
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}
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case Operation::ASLm: {
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const auto value = src.w;
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src.w = uint16_t(value << 1);
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status.extend_flag = status.carry_flag = value & 0x8000;
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set_neg_zero_overflow(src.w, 0x8000);
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} break;
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case Operation::ASLb: asl(dest.b, 8); break;
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case Operation::ASLw: asl(dest.w, 16); break;
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case Operation::ASLl: asl(dest.l, 32); break;
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#define asr(destination, size) {\
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decode_shift_count(decltype(destination)); \
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const auto value = destination; \
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\
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if(!shift_count) { \
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status.carry_flag = 0; \
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} else { \
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destination = (shift_count < size) ? \
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decltype(destination)(\
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(value >> shift_count) | \
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((value & decltype(value)(1 << (size - 1)) ? 0xffffffff : 0x000000000) << (size - shift_count)) \
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) : \
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decltype(destination)( \
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(value & decltype(value)(1 << (size - 1))) ? 0xffffffff : 0x000000000 \
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); \
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status.extend_flag = status.carry_flag = Status::FlagT(value) & Status::FlagT(1 << (shift_count - 1)); \
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} \
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\
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set_neg_zero_overflow(destination, 1 << (size - 1)); \
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}
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case Operation::ASRm: {
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const auto value = src.w;
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src.w = (value&0x8000) | (value >> 1);
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status.extend_flag = status.carry_flag = value & 1;
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set_neg_zero_overflow(src.w, 0x8000);
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} break;
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case Operation::ASRb: asr(dest.b, 8); break;
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case Operation::ASRw: asr(dest.w, 16); break;
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case Operation::ASRl: asr(dest.l, 32); break;
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#undef set_neg_zero_overflow
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#define set_neg_zero_overflow(v, m) \
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set_neg_zero(v, m); \
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status.overflow_flag = 0;
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#undef set_flags
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#define set_flags(v, m, t) \
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status.zero_result = v; \
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@ -850,19 +845,27 @@ template <
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status.overflow_flag = 0; \
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status.carry_flag = value & (t);
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#define lsl(destination, size) {\
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decode_shift_count(decltype(destination)); \
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const auto value = destination; \
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\
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if(!shift_count) { \
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status.carry_flag = 0; \
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} else { \
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destination = (shift_count < size) ? decltype(destination)(value << shift_count) : 0; \
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status.extend_flag = status.carry_flag = Status::FlagT(value) & Status::FlagT( (1u << (size - 1)) >> (shift_count - 1) ); \
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} \
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\
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set_neg_zero_overflow(destination, 1 << (size - 1)); \
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}
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#define set_flags_w(t) set_flags(src.w, 0x8000, t)
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case Operation::ASLm: {
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const auto value = src.w;
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src.w = uint16_t(value << 1);
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status.extend_flag = status.carry_flag = value & 0x8000;
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set_neg_zero_overflow(src.w, 0x8000);
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} break;
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case Operation::ASLb: Primitive::shift<Operation::ASLb>(src.l, dest.b, status, flow_controller); break;
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case Operation::ASLw: Primitive::shift<Operation::ASLw>(src.l, dest.w, status, flow_controller); break;
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case Operation::ASLl: Primitive::shift<Operation::ASLl>(src.l, dest.l, status, flow_controller); break;
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case Operation::ASRm: {
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const auto value = src.w;
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src.w = (value&0x8000) | (value >> 1);
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status.extend_flag = status.carry_flag = value & 1;
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set_neg_zero_overflow(src.w, 0x8000);
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} break;
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case Operation::ASRb: Primitive::shift<Operation::ASRb>(src.l, dest.b, status, flow_controller); break;
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case Operation::ASRw: Primitive::shift<Operation::ASRw>(src.l, dest.w, status, flow_controller); break;
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case Operation::ASRl: Primitive::shift<Operation::ASRl>(src.l, dest.l, status, flow_controller); break;
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case Operation::LSLm: {
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const auto value = src.w;
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@ -870,23 +873,9 @@ template <
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status.extend_flag = status.carry_flag = value & 0x8000;
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set_neg_zero_overflow(src.w, 0x8000);
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} break;
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case Operation::LSLb: lsl(dest.b, 8); break;
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case Operation::LSLw: lsl(dest.w, 16); break;
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case Operation::LSLl: lsl(dest.l, 32); break;
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#define lsr(destination, size) {\
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decode_shift_count(decltype(destination)); \
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const auto value = destination; \
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\
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if(!shift_count) { \
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status.carry_flag = 0; \
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} else { \
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destination = (shift_count < size) ? (value >> shift_count) : 0; \
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status.extend_flag = status.carry_flag = value & Status::FlagT(1 << (shift_count - 1)); \
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} \
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\
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set_neg_zero_overflow(destination, 1 << (size - 1)); \
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}
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case Operation::LSLb: Primitive::shift<Operation::LSLb>(src.l, dest.b, status, flow_controller); break;
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case Operation::LSLw: Primitive::shift<Operation::LSLw>(src.l, dest.w, status, flow_controller); break;
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case Operation::LSLl: Primitive::shift<Operation::LSLl>(src.l, dest.l, status, flow_controller); break;
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case Operation::LSRm: {
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const auto value = src.w;
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@ -894,11 +883,9 @@ template <
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status.extend_flag = status.carry_flag = value & 1;
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set_neg_zero_overflow(src.w, 0x8000);
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} break;
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case Operation::LSRb: lsr(dest.b, 8); break;
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case Operation::LSRw: lsr(dest.w, 16); break;
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case Operation::LSRl: lsr(dest.l, 32); break;
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// ---
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case Operation::LSRb: Primitive::shift<Operation::LSRb>(src.l, dest.b, status, flow_controller); break;
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case Operation::LSRw: Primitive::shift<Operation::LSRw>(src.l, dest.w, status, flow_controller); break;
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case Operation::LSRl: Primitive::shift<Operation::LSRl>(src.l, dest.l, status, flow_controller); break;
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case Operation::ROLm: {
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const auto value = src.w;
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@ -940,15 +927,7 @@ template <
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case Operation::ROXRw: Primitive::rox<Operation::ROXRw>(src.l, dest.w, status, flow_controller); break;
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case Operation::ROXRl: Primitive::rox<Operation::ROXRl>(src.l, dest.l, status, flow_controller); break;
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#undef ror
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#undef rol
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#undef asr
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#undef lsr
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#undef lsl
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#undef asl
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#undef set_flags
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#undef decode_shift_count
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#undef set_flags_w
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#undef set_neg_zero_overflow
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#undef set_neg_zero
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