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mirror of https://github.com/TomHarte/CLK.git synced 2024-11-25 16:31:42 +00:00

Start mutating towards a form that owns the switch.

This commit is contained in:
Thomas Harte 2024-02-21 14:17:01 -05:00
parent 954d920b9e
commit 0fe2c1406b
3 changed files with 146 additions and 48 deletions

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@ -11,10 +11,151 @@
#include "Model.hpp"
#include "Operation.hpp"
#include "../../Reflection/Dispatcher.hpp"
#include <array>
namespace InstructionSet::ARM {
enum class ShiftType {
LogicalLeft = 0b00,
LogicalRight = 0b01,
ArithmeticRight = 0b10,
RotateRight = 0b11,
};
static constexpr int FlagsStartBit = 20;
template <int position>
constexpr bool flag_bit(uint8_t flags) {
static_assert(position >= 20 && position < 28);
return flags & (1 << (position - FlagsStartBit));
}
//
// Data processing (i.e. AND to MVN).
//
struct DataProcessingFlags {
constexpr DataProcessingFlags(uint8_t flags) noexcept : flags_(flags) {}
/// @returns @c true if operand 2 is defined by the @c rotate() and @c immediate() fields;
/// @c false if it is defined by the @c shift_*() and @c operand2() fields.
constexpr bool operand2_is_immediate() { return flag_bit<25>(flags_); }
constexpr bool set_condition_codes() { return flag_bit<20>(flags_); }
private:
uint8_t flags_;
};
struct DataProcessing {
constexpr DataProcessing(uint32_t opcode) noexcept : opcode_(opcode) {}
/// The destination register index. i.e. Rd.
int destination() const { return (opcode_ >> 12) & 0xf; }
/// The operand 1 register index. i.e. Rn.
int operand1() const { return (opcode_ >> 16) & 0xf; }
//
// Register values for operand 2.
//
/// The operand 2 register index if @c operand2_is_immediate() is @c false; meaningless otherwise.
int operand2() const { return opcode_ & 0xf; }
/// The type of shift to apply to operand 2 if @c operand2_is_immediate() is @c false; meaningless otherwise.
ShiftType shift_type() const { return ShiftType((opcode_ >> 5) & 3); }
/// @returns @c true if the amount to shift by should be taken from a register; @c false if it is an immediate value.
bool shift_count_is_register() const { return opcode_ & (1 << 4); }
/// The shift amount register index if @c shift_count_is_register() is @c true; meaningless otherwise.
int shift_register() const { return (opcode_ >> 8) & 0xf; }
/// The amount to shift by if @c shift_count_is_register() is @c false; meaningless otherwise.
int shift_amount() const { return (opcode_ >> 7) & 0x1f; }
//
// Immediate values for operand 2.
//
/// An 8-bit value to rotate right @c rotate() places if @c operand2_is_immediate() is @c true; meaningless otherwise.
int immediate() const { return opcode_ & 0xff; }
/// The number of bits to rotate @c immediate() by to the right if @c operand2_is_immediate() is @c true; meaningless otherwise.
int rotate() const { return (opcode_ >> 7) & 0x1e; }
private:
uint32_t opcode_;
};
//
// MUL and MLA.
//
struct MultiplyFlags {
constexpr MultiplyFlags(uint8_t flags) noexcept : flags_(flags) {}
constexpr bool set_condition_codes() { return flag_bit<20>(flags_); }
private:
uint8_t flags_;
};
struct Multiply {
constexpr Multiply(uint32_t opcode) noexcept : opcode_(opcode) {}
/// The destination register index. i.e. 'Rd'.
int destination() const { return (opcode_ >> 16) & 0xf; }
/// The accumulator register index for multiply-add. i.e. 'Rn'.
int accumulator() const { return (opcode_ >> 12) & 0xf; }
/// The multiplicand register index. i.e. 'Rs'.
int multiplicand() const { return (opcode_ >> 8) & 0xf; }
/// The multiplier register index. i.e. 'Rm'.
int multiplier() const { return opcode_ & 0xf; }
private:
uint32_t opcode_;
};
struct OperationMapper {
template <int i, typename SchedulerT> void dispatch(uint32_t instruction, SchedulerT &scheduler) {
constexpr auto partial = static_cast<uint32_t>(i << 20);
// Data processing; cf. p.17.
if constexpr (((partial >> 26) & 0b11) == 0b00) {
constexpr auto operation = Operation(int(Operation::AND) + ((partial >> 21) & 0xf));
constexpr auto flags = DataProcessingFlags(i);
scheduler.template data_processing<operation, flags>(
DataProcessing(instruction)
);
return;
}
// Multiply and multiply-accumulate (MUL, MLA); cf. p.23.
if(((partial >> 22) & 0b111'111) == 0b000'000) {
if(((instruction >> 4) & 0b1111) != 0b1001) {
scheduler.unknown(instruction);
} else {
constexpr bool is_mla = partial & (1 << 21);
constexpr auto flags = MultiplyFlags(i);
scheduler.template multiply<is_mla ? Operation::MLA : Operation::MUL, flags>(
Multiply(instruction)
);
}
return;
}
}
};
template <typename SchedulerT> void dispatch(uint32_t instruction, SchedulerT &scheduler) {
OperationMapper mapper;
Reflection::dispatch(mapper, (instruction >> 20) & 0xff, instruction, scheduler);
}
/*
template <Model model>
using OperationTable = std::array<Operation, 256>;
@ -113,4 +254,6 @@ constexpr Operation operation(uint32_t opcode) {
return op;
}
*/
}

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@ -14,7 +14,7 @@
namespace InstructionSet::ARM {
enum class ShiftType {
/*enum class ShiftType {
LogicalLeft = 0b00,
LogicalRight = 0b01,
ArithmeticRight = 0b10,
@ -140,7 +140,7 @@ class Instruction {
private:
uint32_t opcode_;
};
};*/
// TODO: do MUL and MLA really transpose Rd and Rn as per the data sheet?
// ARM: Assembly Language Programming by Cockerell thinks not.

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@ -44,39 +44,7 @@ enum class Operation {
/// Rd = NOT Op2.
MVN,
/// Rd = Op1 AND Op2.
ANDS,
/// Rd = Op1 EOR Op2.
EORS,
/// Rd = Op1 - Op2.
SUBS,
/// Rd = Op2 - Op1.
RSBS,
/// Rd = Op1 + Op2.
ADDS,
/// Rd = Op1 + Ord2 + C.
ADCS,
/// Rd = Op1 - Op2 + C.
SBCS,
/// Rd = Op2 - Op1 + C.
RSCS,
/// Set condition codes on Op1 AND Op2.
TSTS,
/// Set condition codes on Op1 EOR Op2.
TEQS,
/// Set condition codes on Op1 - Op2.
CMPS,
/// Set condition codes on Op1 + Op2.
CMNS,
/// Rd = Op1 OR Op2.
ORRS,
/// Rd = Op2
MOVS,
/// Rd = Op1 AND NOT Op2.
BICS,
/// Rd = NOT Op2.
MVNS,
MUL, MLA,
B, BL,
LDR, STR,
@ -87,21 +55,8 @@ enum class Operation {
CoprocessorDataTransfer,
Undefined,
// These are kept at the end for a minor decoding win; they can be only partially decoded
// with the table-based decoder used elsewhere so a special case checks more bits upon
// a MUL or MLA and keeping these at the end of the enum allows a single conditional to
// determine whether the extra decoding is needed.
//
// See is_multiply below.
MUL, MLA,
MULS, MLAS,
};
constexpr bool is_multiply(Operation op) {
return op >= Operation::MUL;
}
enum class Condition {
EQ, NE, CS, CC,
MI, PL, VS, VC,