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Boil down segment ahead of time.

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This commit is contained in:
Thomas Harte 2023-10-27 12:54:42 -04:00
parent 5b0d2d754f
commit 2d70b44303
5 changed files with 30 additions and 53 deletions
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33
InstructionSets/x86/Implementation/PerformImplementation.hpp
View File

@ -184,8 +184,7 @@ IntT *resolve(
// If execution has reached here then a memory fetch is required.
// Do it and exit.
const Source segment = pointer.segment(instruction.segment_override());
return &memory.template access<IntT>(segment, target_address);
return &memory.template access<IntT>(instruction.data_segment(), target_address);
};
namespace Primitive {
@ -859,7 +858,7 @@ void call_far(InstructionT &instruction,
break;
}
const Source source_segment = pointer.segment(instruction.segment_override());
const Source source_segment = instruction.data_segment();
const uint16_t offset = memory.template access<uint16_t>(source_segment, source_address);
source_address += 2;
@ -891,7 +890,7 @@ void jump_far(InstructionT &instruction,
break;
}
const Source source_segment = pointer.segment(instruction.segment_override());
const Source source_segment = instruction.data_segment();
const uint16_t offset = memory.template access<uint16_t>(source_segment, source_address);
source_address += 2;
@ -932,7 +931,7 @@ void ld(
) {
const auto pointer = instruction.source();
auto source_address = address<model, uint16_t>(instruction, pointer, registers, memory);
const Source source_segment = pointer.segment(instruction.segment_override());
const Source source_segment = instruction.data_segment();
destination = memory.template access<uint16_t>(source_segment, source_address);
source_address += 2;
@ -959,15 +958,12 @@ void xlat(
MemoryT &memory,
RegistersT &registers
) {
Source source_segment = instruction.segment_override();
if(source_segment == Source::None) source_segment = Source::DS;
AddressT address;
if constexpr (std::is_same_v<AddressT, uint16_t>) {
address = registers.bx() + registers.al();
}
registers.al() = memory.template access<uint8_t>(source_segment, address);
registers.al() = memory.template access<uint8_t>(instruction.data_segment(), address);
}
template <typename IntT>
@ -1414,10 +1410,7 @@ void cmps(const InstructionT &instruction, AddressT &eCX, AddressT &eSI, Address
return;
}
Source source_segment = instruction.segment_override();
if(source_segment == Source::None) source_segment = Source::DS;
IntT lhs = memory.template access<IntT>(source_segment, eSI);
IntT lhs = memory.template access<IntT>(instruction.data_segment(), eSI);
const IntT rhs = memory.template access<IntT>(Source::ES, eDI);
eSI += status.direction<AddressT>() * sizeof(IntT);
eDI += status.direction<AddressT>() * sizeof(IntT);
@ -1447,10 +1440,7 @@ void lods(const InstructionT &instruction, AddressT &eCX, AddressT &eSI, IntT &e
return;
}
Source source_segment = instruction.segment_override();
if(source_segment == Source::None) source_segment = Source::DS;
eAX = memory.template access<IntT>(source_segment, eSI);
eAX = memory.template access<IntT>(instruction.data_segment(), eSI);
eSI += status.direction<AddressT>() * sizeof(IntT);
repeat<AddressT, repetition>(eCX, flow_controller);
@ -1462,10 +1452,7 @@ void movs(const InstructionT &instruction, AddressT &eCX, AddressT &eSI, Address
return;
}
Source source_segment = instruction.segment_override();
if(source_segment == Source::None) source_segment = Source::DS;
memory.template access<IntT>(Source::ES, eDI) = memory.template access<IntT>(source_segment, eSI);
memory.template access<IntT>(Source::ES, eDI) = memory.template access<IntT>(instruction.data_segment(), eSI);
eSI += status.direction<AddressT>() * sizeof(IntT);
eDI += status.direction<AddressT>() * sizeof(IntT);
@ -1491,9 +1478,7 @@ void outs(const InstructionT &instruction, AddressT &eCX, uint16_t port, Address
return;
}
Source source_segment = instruction.segment_override();
if(source_segment == Source::None) source_segment = Source::DS;
io.template out<IntT>(port, memory.template access<IntT>(source_segment, eSI));
io.template out<IntT>(port, memory.template access<IntT>(instruction.data_segment(), eSI));
eSI += status.direction<AddressT>() * sizeof(IntT);
repeat<AddressT, repetition>(eCX, flow_controller);

11
InstructionSets/x86/Instruction.cpp
View File

@ -425,14 +425,7 @@ std::string InstructionSet::x86::to_string(
}
stream << '[';
Source segment = instruction.segment_override();
if(segment == Source::None) {
segment = pointer.default_segment();
if(segment == Source::None) {
segment = Source::DS;
}
}
stream << InstructionSet::x86::to_string(segment, InstructionSet::x86::DataSize::None) << ':';
stream << InstructionSet::x86::to_string(instruction.data_segment(), InstructionSet::x86::DataSize::None) << ':';
bool addOffset = false;
switch(source) {
@ -492,7 +485,7 @@ std::string InstructionSet::x86::to_string(
case Operation::INS_REP:
case Operation::OUTS:
case Operation::OUTS_REP:
switch(instruction.second.segment_override()) {
switch(instruction.second.data_segment()) {
default: break;
case Source::ES: operation += "es "; break;
case Source::CS: operation += "cs "; break;

23
InstructionSets/x86/Instruction.hpp
View File

@ -644,13 +644,6 @@ class DataPointer {
}
}
constexpr Source segment(Source segment_override) const {
// TODO: remove conditionality here.
if(segment_override != Source::None) return segment_override;
if(const auto segment = default_segment(); segment != Source::None) return segment;
return Source::DS;
}
constexpr Source base() const {
return sib_.base();
}
@ -767,11 +760,9 @@ template<bool is_32bit> class Instruction {
return AddressSize(mem_exts_source_ >> 7);
}
/// @returns @c Source::None if no segment override was found; the overridden segment otherwise.
/// On x86 a segment override cannot modify the segment used as a destination in string instructions,
/// or that used by stack instructions, but this function does not spend the time necessary to provide
/// the correct default for those.
Source segment_override() const {
/// @returns @c Source::None if no segment is applicable; the segment to use for any
/// memory-accessing source otherwise.
Source data_segment() const {
return Source(
int(Source::ES) +
((source_data_dest_sib_ >> 10) & 7)
@ -826,7 +817,6 @@ template<bool is_32bit> class Instruction {
source_data_dest_sib_(uint16_t(
(int(data_size) << 14) |
(lock ? (1 << 13) : 0) |
((int(segment_override)&7) << 10) |
((uint8_t(sib) & 0xf8) << 2) |
int(destination) |
(destination == Source::Indirect ? (uint8_t(sib) & 7) : 0)
@ -843,6 +833,13 @@ template<bool is_32bit> class Instruction {
extensions_[extension] = ImmediateT(displacement);
++extension;
}
// Patch in a fully-resolved segment.
Source segment = segment_override;
if(segment == Source::None) segment = this->source().default_segment();
if(segment == Source::None) segment = this->destination().default_segment();
if(segment == Source::None) segment = Source::DS;
source_data_dest_sib_ |= (int(segment)&7) << 10;
}
};

10
OSBindings/Mac/Clock SignalTests/8088Tests.mm
View File

@ -419,10 +419,9 @@ struct FailedExecution {
// Attempt clerical reconciliation:
//
// The test suite retains a distinction between SHL and SAL, which the decoder doesn't. So consider that
// a potential point of difference.
//
// Also, the decoder treats INT3 and INT 3 as the same thing. So allow for a meshing of those.
// * the test suite retains a distinction between SHL and SAL, which the decoder doesn't;
// * the decoder treats INT3 and INT 3 as the same thing; and
// * the decoder doesn't record whether a segment override was present, just the final segment.
int adjustment = 7;
while(!isEqual && adjustment) {
NSString *alteredName = [test[@"name"] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
@ -433,6 +432,9 @@ struct FailedExecution {
if(adjustment & 1) {
alteredName = [alteredName stringByReplacingOccurrencesOfString:@"int3" withString:@"int 3h"];
}
if(adjustment & 4) {
alteredName = [@"ds " stringByAppendingString:alteredName];
}
isEqual = compare_decoding(alteredName);
--adjustment;

6
OSBindings/Mac/Clock SignalTests/x86DecoderTests.mm
View File

@ -410,7 +410,7 @@ decode(const std::initializer_list<uint8_t> &stream, bool set_32_bit = false) {
// add DWORD PTR [edi-0x42],0x9f683aa9
// lock jp 0xfffffff0 (from 0000000e)
test(instructions[0], DataSize::DWord, Operation::INC, Source::eDX);
XCTAssertEqual(instructions[0].segment_override(), Source::CS);
XCTAssertEqual(instructions[0].data_segment(), Source::CS);
test(instructions[1], DataSize::Byte, Operation::OR, Source::Immediate, Source::eAX, 0x9);
test(instructions[2], DataSize::DWord, Operation::ADD, Source::Immediate, ScaleIndexBase(Source::eDI), 0x9f683aa9, -0x42);
test(instructions[3], Operation::JP, 0, -30);
@ -421,7 +421,7 @@ decode(const std::initializer_list<uint8_t> &stream, bool set_32_bit = false) {
// stos BYTE PTR es:[edi],al
// pusha
test(instructions[4], DataSize::Byte, Operation::MOV, Source::Immediate, Source::AH, 0xc1);
XCTAssertEqual(instructions[4].segment_override(), Source::DS);
XCTAssertEqual(instructions[4].data_segment(), Source::DS);
test(instructions[5], DataSize::Word, Operation::POP, Source::None, Source::DS);
test(instructions[6], DataSize::Byte, Operation::STOS);
test(instructions[7], Operation::PUSHA);
@ -464,7 +464,7 @@ decode(const std::initializer_list<uint8_t> &stream, bool set_32_bit = false) {
test(instructions[21], DataSize::Byte, Operation::XOR, Source::Immediate, Source::eAX, 0x45);
test(instructions[22], DataSize::DWord, Operation::LDS, ScaleIndexBase(Source::eCX), Source::eDX);
test(instructions[23], DataSize::Byte, Operation::MOV, Source::eAX, Source::DirectAddress, 0xe4dba6d3);
XCTAssertEqual(instructions[23].segment_override(), Source::DS);
XCTAssertEqual(instructions[23].data_segment(), Source::DS);
// pop ds
// movs DWORD PTR es:[edi],DWORD PTR ds:[esi]