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-rw-r--r--instructions.md18
-rw-r--r--qtmips_machine/alu.cpp4
-rw-r--r--qtmips_machine/alu.h2
-rw-r--r--qtmips_machine/core.cpp140
-rw-r--r--qtmips_machine/core.h10
-rw-r--r--qtmips_machine/memory.cpp3
-rw-r--r--qtmips_machine/registers.cpp4
-rw-r--r--qtmips_machine/registers.h1
-rw-r--r--qtmips_machine/tests/testcore.cpp99
-rw-r--r--qtmips_machine/tests/tst_machine.h4
10 files changed, 231 insertions, 54 deletions
diff --git a/instructions.md b/instructions.md
index 87d4dd5..fbd5559 100644
--- a/instructions.md
+++ b/instructions.md
@@ -33,20 +33,20 @@ CPU Arithmetic Instruction
CPU Branch and Jump Instructions
--------------------------------
-* [ ] B
+* [x] B
* [ ] BAL
-* [ ] BEQ
-* [ ] BGEZ
+* [x] BEQ
+* [x] BGEZ
* [ ] BGEZAL
-* [ ] BGTZ
-* [ ] BLEZ
-* [ ] BLTZ
+* [x] BGTZ
+* [x] BLEZ
+* [x] BLTZ
* [ ] BLTZAL
-* [ ] BNE
-* [ ] J
+* [x] BNE
+* [x] J
* [ ] JAL
* [ ] JALR
-* [ ] JR
+* [x] JR
CPU No Instructions
-------------------
diff --git a/qtmips_machine/alu.cpp b/qtmips_machine/alu.cpp
index 0350412..73c49e4 100644
--- a/qtmips_machine/alu.cpp
+++ b/qtmips_machine/alu.cpp
@@ -17,6 +17,10 @@ std::uint32_t alu_operate(enum AluOp operation, std::uint32_t s, std::uint32_t t
case ALU_OP_SRAV:
// TODO is this correct implementation? (Should we be masking top most bit?)
return ((t & 0x7fffffff) >> s) | (t & 0x80000000);
+ case ALU_OP_JR:
+ case ALU_OP_JALR:
+ // Do nothing as we solve this when we are handling program counter in instruction decode (handle_pc)
+ return 0;
case ALU_OP_MOVZ:
// We do this just to implement valid alu operation but we have to evaluate comparison way before this to disable register write
return t == 0 ? s : 0;
diff --git a/qtmips_machine/alu.h b/qtmips_machine/alu.h
index 4818bb1..95042f4 100644
--- a/qtmips_machine/alu.h
+++ b/qtmips_machine/alu.h
@@ -14,6 +14,8 @@ enum AluOp : std::uint8_t {
ALU_OP_SLLV,
ALU_OP_SRLV = 6,
ALU_OP_SRAV,
+ ALU_OP_JR,
+ ALU_OP_JALR,
ALU_OP_MOVZ = 10,
ALU_OP_MOVN,
ALU_OP_MFHI = 16,
diff --git a/qtmips_machine/core.cpp b/qtmips_machine/core.cpp
index 20c1b74..93b83dd 100644
--- a/qtmips_machine/core.cpp
+++ b/qtmips_machine/core.cpp
@@ -7,7 +7,6 @@
#define DM_ALUSRC (1L<<3)
#define DM_REGD (1L<<4)
#define DM_REGWRITE (1L<<5)
-#define DM_BRANCH (1L<<6)
struct DecodeMap {
long flags;
@@ -16,20 +15,21 @@
// This is temporally operation place holder
-#define NOPE { .flags = 0, .alu = ALU_OP_SLL }
+#define NOALU .alu = ALU_OP_SLL
+#define NOPE { .flags = 0, NOALU }
#define FLAGS_ALU_I (DM_SUPPORTED | DM_ALUSRC | DM_REGWRITE)
// This is map from opcode to signals.
static const struct DecodeMap dmap[] = {
- { .flags = DM_SUPPORTED | DM_REGD | DM_REGWRITE, .alu = ALU_OP_SLL }, // Alu operations
- NOPE, // Branch on alu operations
- NOPE, // J
+ { .flags = DM_SUPPORTED | DM_REGD | DM_REGWRITE, NOALU }, // Alu operations (aluop is decoded from function explicitly)
+ { .flags = DM_SUPPORTED, NOALU }, // REGIMM (BLTZ, BGEZ, )
+ { .flags = DM_SUPPORTED, NOALU }, // J
NOPE, // JAL
- NOPE, // BEQ
- NOPE, // BNE
- NOPE, // BLEZ
- NOPE, // BGTZ
+ { .flags = DM_SUPPORTED, NOALU }, // BEQ
+ { .flags = DM_SUPPORTED, NOALU }, // BNE
+ { .flags = DM_SUPPORTED, NOALU }, // BLEZ
+ { .flags = DM_SUPPORTED, NOALU }, // BGTZ
{ .flags = FLAGS_ALU_I, .alu = ALU_OP_ADD }, // ADDI
{ .flags = FLAGS_ALU_I, .alu = ALU_OP_ADDU }, // ADDIU
{ .flags = FLAGS_ALU_I, .alu = ALU_OP_SLT }, // SLTI
@@ -96,7 +96,6 @@ Core::Core(Registers *regs, MemoryAccess *mem) {
struct Core::dtFetch Core::fetch() {
// TODO signals
Instruction inst(mem->read_word(regs->read_pc()));
- regs->pc_inc();
return {
.inst = inst
};
@@ -104,10 +103,14 @@ struct Core::dtFetch Core::fetch() {
struct Core::dtDecode Core::decode(struct dtFetch dt) {
struct DecodeMap dec = dmap[dt.inst.opcode()];
- if (!dec.flags & DM_SUPPORTED)
+ if (!(dec.flags & DM_SUPPORTED))
// TODO message
throw QTMIPS_EXCEPTION(UnsupportedInstruction, "", "");
+ // TODO solve forwarding somehow in here
+ std::uint32_t rs = regs->read_gp(dt.inst.rs());
+ std::uint32_t rt = regs->read_gp(dt.inst.rt());
+
return {
.inst = dt.inst,
.mem2reg = dec.flags & DM_MEM2REG,
@@ -115,10 +118,9 @@ struct Core::dtDecode Core::decode(struct dtFetch dt) {
.alusrc = dec.flags & DM_ALUSRC,
.regd = dec.flags & DM_REGD,
.regwrite = dec.flags & DM_REGWRITE,
- .branch = dec.flags & DM_BRANCH,
.aluop = dt.inst.opcode() == 0 ? (enum AluOp)dt.inst.funct() : dec.alu,
- .val_rs = regs->read_gp(dt.inst.rs()),
- .val_rt = regs->read_gp(dt.inst.rt()),
+ .val_rs = rs,
+ .val_rt = rt,
};
// TODO on jump there should be delay slot. Does processor addes it or compiler. And do we care?
}
@@ -154,9 +156,88 @@ void Core::writeback(struct dtMemory dt) {
}
}
+void Core::handle_pc(struct dtDecode dt) {
+ // TODO signals
+ bool branch = false;
+ bool link = false;
+ // TODO implement link
+
+ switch (dt.inst.opcode()) {
+ case 0: // JR (JALR)
+ if (dt.inst.funct() == ALU_OP_JR || dt.inst.funct() == ALU_OP_JALR) {
+ regs->pc_abs_jmp(dt.val_rs);
+ return;
+ }
+ break;
+ case 1: // REGIMM instruction
+ //switch (dt.inst.rt() & 0xF) { // Should be used when linking is supported
+ switch (dt.inst.rt()) {
+ case 0: // BLTZ(AL)
+ branch = (std::int32_t)dt.val_rs < 0;
+ break;
+ case 1: // BGEZ(AL)
+ branch = (std::int32_t)dt.val_rs >= 0;
+ break;
+ default:
+ throw QTMIPS_EXCEPTION(UnsupportedInstruction, "REGIMM instruction with unknown rt code", QString::number(dt.inst.rt(), 16));
+ }
+ link = dt.inst.rs() & 0x10;
+ break;
+ case 2: // J
+ case 3: // JAL
+ regs->pc_abs_jmp_28(dt.inst.address() << 2);
+ return;
+ case 4: // BEQ
+ branch = dt.val_rs == dt.val_rt;
+ break;
+ case 5: // BNE
+ branch = dt.val_rs != dt.val_rt;
+ break;
+ case 6: // BLEZ
+ branch = (std::int32_t)dt.val_rs <= 0;
+ break;
+ case 7: // BGTZ
+ branch = (std::int32_t)dt.val_rs > 0;
+ break;
+ }
+
+ if (branch)
+ regs->pc_jmp((std::int32_t)(((dt.inst.immediate() & 0x7fff) << 2) | ((dt.inst.immediate() & 0x8000) << 16)));
+ else
+ regs->pc_inc();
+}
+
+void Core::dtFetchInit(struct dtFetch &dt) {
+ dt.inst = Instruction(0x00);
+}
+
+void Core::dtDecodeInit(struct dtDecode &dt) {
+ dt.inst = Instruction(0x00);
+ dt.mem2reg = false;
+ dt.memwrite = false;
+ dt.alusrc = false;
+ dt.regd = false;
+ dt.regwrite = false;
+ dt.aluop = ALU_OP_SLL;
+ dt.val_rs = 0;
+ dt.val_rt = 0;
+}
+
+void Core::dtExecuteInit(struct dtExecute &dt) {
+ dt.regwrite = false;
+ dt.rwrite = false;
+ dt.alu_val = 0;
+}
+
+void Core::dtMemoryInit(struct dtMemory &dt) {
+ dt.regwrite = false;
+ dt.rwrite = false;
+ dt.alu_val = 0;
+}
+
CoreSingle::CoreSingle(Registers *regs, MemoryAccess *mem) : \
Core(regs, mem) {
- // Nothing to do
+ dtDecodeInit(jmp_delay_decode);
}
void CoreSingle::step() {
@@ -165,32 +246,16 @@ void CoreSingle::step() {
struct dtExecute e = execute(d);
struct dtMemory m = memory(e);
writeback(m);
+ handle_pc(jmp_delay_decode);
+ jmp_delay_decode = d; // Copy current decode
}
CorePipelined::CorePipelined(Registers *regs, MemoryAccess *mem) : \
Core(regs, mem) {
- // Initialize to NOPE //
- // dtFetch
- dt_f.inst = Instruction(0x00);
- // dtDecode
- dt_d.inst = dt_f.inst;
- dt_d.mem2reg = false;
- dt_d.memwrite = false;
- dt_d.alusrc = false;
- dt_d.regd = false;
- dt_d.regwrite = false;
- dt_d.branch = false;
- dt_d.aluop = ALU_OP_SLL;
- dt_d.val_rs = 0;
- dt_d.val_rt = 0;
- // dtExecute
- dt_e.regwrite = dt_d.regwrite;
- dt_e.rwrite = dt_d.regwrite;
- dt_e.alu_val = 0;
- // dtMemory
- dt_m.regwrite = dt_e.regwrite;
- dt_m.rwrite = dt_e.rwrite;
- dt_m.alu_val = dt_e.alu_val;
+ dtFetchInit(dt_f);
+ dtDecodeInit(dt_d);
+ dtExecuteInit(dt_e);
+ dtMemoryInit(dt_m);
}
void CorePipelined::step() {
@@ -200,4 +265,5 @@ void CorePipelined::step() {
dt_e = execute(dt_d);
dt_d = decode(dt_f);
dt_f = fetch();
+ handle_pc(dt_d);
}
diff --git a/qtmips_machine/core.h b/qtmips_machine/core.h
index b566a38..6366088 100644
--- a/qtmips_machine/core.h
+++ b/qtmips_machine/core.h
@@ -31,7 +31,6 @@ protected:
bool alusrc; // If second value to alu is immediate value (rt used otherwise)
bool regd; // If rd is used (otherwise rt is used for write target)
bool regwrite; // If output should be written back to register (which one depends on regd)
- bool branch; // If this is branch instruction
enum AluOp aluop; // Decoded ALU operation
std::uint32_t val_rs; // Value from register rs
std::uint32_t val_rt; // Value from register rt
@@ -54,7 +53,13 @@ protected:
struct dtExecute execute(struct dtDecode);
struct dtMemory memory(struct dtExecute);
void writeback(struct dtMemory);
+ void handle_pc(struct dtDecode);
+ // Initialize structures to NOPE instruction
+ void dtFetchInit(struct dtFetch &dt);
+ void dtDecodeInit(struct dtDecode &dt);
+ void dtExecuteInit(struct dtExecute &dt);
+ void dtMemoryInit(struct dtMemory &dt);
};
class CoreSingle : public Core {
@@ -62,6 +67,9 @@ public:
CoreSingle(Registers *regs, MemoryAccess *mem);
void step();
+
+private:
+ struct Core::dtDecode jmp_delay_decode;
};
class CorePipelined : public Core {
diff --git a/qtmips_machine/memory.cpp b/qtmips_machine/memory.cpp
index ef4c7e2..282a9e9 100644
--- a/qtmips_machine/memory.cpp
+++ b/qtmips_machine/memory.cpp
@@ -240,8 +240,9 @@ union MemoryTree *Memory::copy_section_tree(const union MemoryTree *mt, size_t d
union MemoryTree *nmt = allocate_section_tree();
if (depth < (MEMORY_TREE_H - 1)) { // Following level is memory tree
for (int i = 0; i < MEMORY_TREE_LEN; i++) {
- if (mt[i].mt != nullptr)
+ if (mt[i].mt != nullptr) {
nmt[i].mt = copy_section_tree(mt[i].mt, depth + 1);
+ }
}
} else { // Following level is memory section
for (int i = 0; i < MEMORY_TREE_LEN; i++) {
diff --git a/qtmips_machine/registers.cpp b/qtmips_machine/registers.cpp
index 5bb852e..a18421e 100644
--- a/qtmips_machine/registers.cpp
+++ b/qtmips_machine/registers.cpp
@@ -46,6 +46,10 @@ void Registers::pc_abs_jmp(std::uint32_t address) {
this->pc = address;
}
+void Registers::pc_abs_jmp_28(std::uint32_t address) {
+ this->pc_abs_jmp((pc & 0xF0000000) | (address & 0x0FFFFFFF));
+}
+
std::uint32_t Registers::read_gp(std::uint8_t i) const {
SANITY_ASSERT(i < 32, QString("Trying to read from register ") + QString(i));
if (!i) // $0 always reads as 0
diff --git a/qtmips_machine/registers.h b/qtmips_machine/registers.h
index 387b59d..dd7e393 100644
--- a/qtmips_machine/registers.h
+++ b/qtmips_machine/registers.h
@@ -14,6 +14,7 @@ public:
std::uint32_t pc_inc(); // Increment program counter by four bytes
std::uint32_t pc_jmp(std::int32_t offset); // Relative jump from current location in program counter
void pc_abs_jmp(std::uint32_t address); // Absolute jump in program counter (write to pc)
+ void pc_abs_jmp_28(std::uint32_t address); // Absolute jump in current 256MB section (basically J implementation)
std::uint32_t read_gp(std::uint8_t i) const; // Read general-purpose register
void write_gp(std::uint8_t i, std::uint32_t value); // Write general-purpose register
diff --git a/qtmips_machine/tests/testcore.cpp b/qtmips_machine/tests/testcore.cpp
index 27a49b4..593483a 100644
--- a/qtmips_machine/tests/testcore.cpp
+++ b/qtmips_machine/tests/testcore.cpp
@@ -175,9 +175,6 @@ void MachineTests::pipecore_regs_data() {
core_regs_data();
}
-#include <iostream>
-using namespace std;
-
void MachineTests::singlecore_regs() {
QFETCH(Instruction, i);
QFETCH(Registers, init);
@@ -208,16 +205,106 @@ void MachineTests::pipecore_regs() {
res.pc_jmp(0x14);
CorePipelined core(&init, &mem_used);
- for (int i = 0; i < 4; i++) {
+ for (int i = 0; i < 5; i++)
core.step(); // Fire steps for five pipelines stages
- }
- core.step();
//cout << "well:" << init.read_gp(26) << ":" << regs_used.read_gp(26) << endl;
QCOMPARE(init, res); // After doing changes from initial state this should be same state as in case of passed expected result
QCOMPARE(mem, mem_used); // There should be no change in memory
}
+static void core_jmp_data() {
+ QTest::addColumn<Instruction>("i");
+ QTest::addColumn<Registers>("regs");
+ QTest::addColumn<std::uint32_t>("pc");
+
+ Registers regs;
+ regs.write_gp(14, -22);
+ regs.write_gp(15, 22);
+ regs.write_gp(16, -22);
+ QTest::newRow("B") << Instruction(4, 0, 0, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("BEQ") << Instruction(4, 14, 16, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("BNE") << Instruction(5, 14, 15, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("BGEZ") << Instruction(1, 15, 1, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("BGTZ") << Instruction(7, 15, 0, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("BLEZ") << Instruction(6, 14, 0, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("BLTZ") << Instruction(1, 14, 0, 61) \
+ << regs \
+ << regs.read_pc() + 4 + (61 << 2);
+ QTest::newRow("J") << Instruction(2, 24) \
+ << regs \
+ << 0x80000000 + (24 << 2);
+ /*
+ QTest::newRow("JR") << Instruction(1, 15, 0, 61) \
+ << regs \
+ << regs.read_pc() + (24 << 2);
+ */
+}
+
+void MachineTests::singlecore_jmp_data() {
+ core_jmp_data();
+}
+
+void MachineTests::pipecore_jmp_data() {
+ core_jmp_data();
+}
+
+void MachineTests::singlecore_jmp() {
+ QFETCH(Instruction, i);
+ QFETCH(Registers, regs);
+ QFETCH(std::uint32_t, pc);
+
+ Memory mem;
+ mem.write_word(regs.read_pc(), i.data());
+ Memory mem_used(mem);
+ Registers regs_used(regs);
+
+ CoreSingle core(&regs_used, &mem_used);
+ core.step();
+ QCOMPARE(regs.read_pc() + 4, regs_used.read_pc()); // First execute delay slot
+ core.step();
+ QCOMPARE(pc, regs_used.read_pc()); // Now do jump
+
+ QCOMPARE(mem, mem_used); // There should be no change in memory
+ regs_used.pc_abs_jmp(regs.read_pc()); // Reset program counter before we do registers compare
+ QCOMPARE(regs, regs_used); // There should be no change in registers now
+}
+
+void MachineTests::pipecore_jmp() {
+ QFETCH(Instruction, i);
+ QFETCH(Registers, regs);
+ QFETCH(std::uint32_t, pc);
+
+ Memory mem;
+ mem.write_word(regs.read_pc(), i.data());
+ Memory mem_used(mem);
+ Registers regs_used(regs);
+
+ CorePipelined core(&regs_used, &mem_used);
+ core.step();
+ QCOMPARE(regs.read_pc() + 4, regs_used.read_pc()); // First just fetch
+ core.step();
+ QCOMPARE(pc, regs_used.read_pc()); // Now do jump
+ for (int i = 0; i < 3; i++)
+ core.step(); // Follow up with three other steps to complete pipeline to be sure that instruction has no side effects
+
+ QCOMPARE(mem, mem_used); // There should be no change in memory
+ regs.pc_abs_jmp(pc + 12); // Set reference pc to three more instructions later (where regs_used should be)
+ QCOMPARE(regs, regs_used); // There should be no change in registers now (except pc)
+}
+
void MachineTests::core_mem_data() {
}
diff --git a/qtmips_machine/tests/tst_machine.h b/qtmips_machine/tests/tst_machine.h
index 3feaddd..9b33e68 100644
--- a/qtmips_machine/tests/tst_machine.h
+++ b/qtmips_machine/tests/tst_machine.h
@@ -34,6 +34,10 @@ private Q_SLOTS:
void singlecore_regs_data();
void pipecore_regs();
void pipecore_regs_data();
+ void singlecore_jmp();
+ void singlecore_jmp_data();
+ void pipecore_jmp();
+ void pipecore_jmp_data();
void core_mem();
void core_mem_data();
};
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-22 07:17:21 +0000