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Takes a run at JSR and RTS.

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This commit is contained in:
Thomas Harte 2019-04-15 15:14:38 -04:00
parent 62e4c23961
commit 1460a88bb3
3 changed files with 123 additions and 9 deletions
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13
Processors/68000/Implementation/68000Implementation.hpp
View File

@ -52,11 +52,13 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
// no instruction was ongoing. Either way, do a standard instruction operation.
// TODO: unless an interrupt is pending, or the trap flag is set.
if(address_[5].full > 0x3fff0 || program_counter_.full < 0x16a) {
std::cout << std::setfill('0');
std::cout << (extend_flag_ ? 'x' : '-') << (negative_flag_ ? 'n' : '-') << (zero_result_ ? '-' : 'z');
std::cout << (overflow_flag_ ? 'v' : '-') << (carry_flag_ ? 'c' : '-') << '\t';
for(int c = 0; c < 8; ++ c) std::cout << "d" << c << ":" << std::setw(8) << data_[c].full << " ";
for(int c = 0; c < 8; ++ c) std::cout << "a" << c << ":" << std::setw(8) << address_[c].full << " ";
}
std::cout << '\n';
decoded_instruction_ = prefetch_queue_.halves.high.full;
@ -831,6 +833,17 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
}
} break;
case int(MicroOp::Action::PrepareJSR):
destination_bus_data_[0] = program_counter_;
effective_address_[1].full = address_[7].full - 2;
address_[7].full -= 4;
break;
case int(MicroOp::Action::PrepareRTS):
effective_address_[0].full = address_[7].full;
address_[7].full += 4;
break;
case int(MicroOp::Action::CopyNextWord):
next_word_ = prefetch_queue_.halves.low.full;
break;

100
Processors/68000/Implementation/68000Storage.cpp
View File

@ -95,8 +95,8 @@ struct ProcessorStorageConstructor {
* nr: read LSW of soemthing from the bus into the source latch;
* nRd: read MSW of something from the bus into the destination latch;
* nrd: read LSW of soemthing from the bus into the destination latch;
* nS: push the MSW of something onto the stack;
* ns: push the LSW of something onto the stack;
* nS: push the MSW of something onto the stack **and then** decrement the pointer;
* ns: push the LSW of something onto the stack **and then** decrement the pointer;
* nU: pop the MSW of something from the stack;
* nu: pop the LSW of something from the stack;
* nV: fetch a vector's MSW;
@ -226,7 +226,7 @@ struct ProcessorStorageConstructor {
if(token == "nR" || token == "nr" || token == "nW" || token == "nw" || token == "nRd" || token == "nrd") {
const bool is_read = tolower(token[1]) == 'r';
const bool use_source_storage = is_read && token.size() != 3;
RegisterPair32 *scratch_data = use_source_storage ? &storage_.source_bus_data_[0] : &storage_.destination_bus_data_[0];
RegisterPair32 *const scratch_data = use_source_storage ? &storage_.source_bus_data_[0] : &storage_.destination_bus_data_[0];
assert(address_iterator != addresses.end());
@ -252,6 +252,42 @@ struct ProcessorStorageConstructor {
continue;
}
// A stack write.
if(token == "nS" || token == "ns") {
RegisterPair32 *const scratch_data = &storage_.destination_bus_data_[0];
step.microcycle.length = HalfCycles(5);
step.microcycle.operation = Microcycle::NewAddress;
step.microcycle.address = &storage_.effective_address_[1].full;
step.microcycle.value = isupper(token[1]) ? &scratch_data->halves.high : &scratch_data->halves.low;
steps.push_back(step);
step.microcycle.length = HalfCycles(3);
step.microcycle.operation |= Microcycle::SelectWord;
step.action = Action::DecrementEffectiveAddress1;
steps.push_back(step);
continue;
}
// A stack read.
if(token == "nU" || token == "nu") {
RegisterPair32 *const scratch_data = &storage_.source_bus_data_[0];
step.microcycle.length = HalfCycles(5);
step.microcycle.operation = Microcycle::NewAddress | Microcycle::Read;
step.microcycle.address = &storage_.effective_address_[0].full;
step.microcycle.value = isupper(token[1]) ? &scratch_data->halves.high : &scratch_data->halves.low;
steps.push_back(step);
step.microcycle.length = HalfCycles(3);
step.microcycle.operation |= Microcycle::SelectWord;
step.action = Action::IncrementEffectiveAddress0;
steps.push_back(step);
continue;
}
std::cerr << "MC68000 program builder; Unknown access token " << token << std::endl;
assert(false);
}
@ -327,7 +363,10 @@ struct ProcessorStorageConstructor {
MOVEM, // Maps a mode and register as they were a 'destination' and sets up bus steps with a suitable
// hole for the runtime part to install proper MOVEM activity.
TST, // Mapsa mode and register to a TST.
TST, // Maps a mode and register to a TST.
JSR, // Maps a mode and register to a JSR.
RTS, // Maps
};
using Operation = ProcessorStorage::Operation;
@ -393,6 +432,8 @@ struct ProcessorStorageConstructor {
{0xffff, 0x4e70, Operation::None, Decoder::RESET}, // 6-83 (p537)
{0xffc0, 0x4ec0, Operation::JMP, Decoder::JMP}, // 4-108 (p212)
{0xffc0, 0x4e80, Operation::JMP, Decoder::JSR}, // 4-109 (p213)
{0xffff, 0x4e75, Operation::JMP, Decoder::RTS}, // 4-169 (p273)
{0xf0c0, 0x9000, Operation::SUBb, Decoder::ADDSUB}, // 4-174 (p278)
{0xf0c0, 0x9040, Operation::SUBw, Decoder::ADDSUB}, // 4-174 (p278)
@ -473,6 +514,7 @@ struct ProcessorStorageConstructor {
{0xffc0, 0x4a00, Operation::TSTb, Decoder::TST}, // 4-192 (p296)
{0xffc0, 0x4a40, Operation::TSTw, Decoder::TST}, // 4-192 (p296)
{0xffc0, 0x4a80, Operation::TSTl, Decoder::TST}, // 4-192 (p296)
};
#ifndef NDEBUG
@ -1454,6 +1496,52 @@ struct ProcessorStorageConstructor {
} break;
case Decoder::JSR: {
storage_.instructions[instruction].source = &storage_.effective_address_[0];
const int mode = combined_mode(ea_mode, ea_register);
switch(mode) {
default: continue;
case Ind: // JSR (An)
storage_.instructions[instruction].source = &storage_.address_[ea_register];
op(Action::PrepareJSR);
op(Action::PerformOperation, seq("np nS ns np"));
break;
case d16PC: // JSR (d16, PC)
case d16An: // JSR (d16, An)
op(Action::PrepareJSR);
op(calc_action_for_mode(mode) | MicroOp::SourceMask, seq("n np nS ns np"));
op(Action::PerformOperation);
break;
case d8PCXn: // JSR (d8, PC, Xn)
case d8AnXn: // JSR (d8, An, Xn)
op(Action::PrepareJSR);
op(calc_action_for_mode(mode) | MicroOp::SourceMask, seq("n nn np nS ns np"));
op(Action::PerformOperation);
break;
case XXXl: // JMP (xxx).L
op(Action::None, seq("np"));
op(Action::PrepareJSR);
op(address_assemble_for_mode(mode) | MicroOp::SourceMask);
op(Action::PerformOperation, seq("n np nS ns np"));
break;
case XXXw: // JSR (xxx).W
op(Action::PrepareJSR);
op(address_assemble_for_mode(mode) | MicroOp::SourceMask);
op(Action::PerformOperation, seq("n np nS ns np"));
break;
}
} break;
case Decoder::RTS: {
storage_.instructions[instruction].source = &storage_.source_bus_data_[0];
op(Action::PrepareRTS, seq("nU nu"));
op(Action::PerformOperation, seq("np np"));
} break;
case Decoder::JMP: {
storage_.instructions[instruction].source = &storage_.effective_address_[0];
const int mode = combined_mode(ea_mode, ea_register);
@ -1478,6 +1566,10 @@ struct ProcessorStorageConstructor {
case XXXl: // JMP (xxx).L
op(Action::None, seq("np"));
op(address_assemble_for_mode(mode) | MicroOp::SourceMask);
op(Action::PerformOperation, seq("np np"));
break;
case XXXw: // JMP (xxx).W
op(address_assemble_for_mode(mode) | MicroOp::SourceMask);
op(Action::PerformOperation, seq("n np np"));

9
Processors/68000/Implementation/68000Storage.hpp
View File

@ -221,6 +221,15 @@ class ProcessorStorage {
/// Performs write-back of pre-decrement address.
MOVEMtoMComplete,
// (i) copies the current program counter to destination_bus_data_;
// (ii) copies the stack pointer minus 2 to effective_address_[1];
// (iii) decrements the stack pointer by four.
PrepareJSR,
// (i) copies the stack pointer to effective_address_[0];
// (ii) increments the stack pointer by four.
PrepareRTS,
};
static const int SourceMask = 1 << 30;
static const int DestinationMask = 1 << 29;