Implement instructions for moving from and to HI and LO registers

6 files changed, 118 insertions, 14 deletions

diff --git a/instructions.md b/instructions.md
index bfd936e..7682226 100644
--- a/instructions.md
+++ b/instructions.md
@@ -86,10 +86,10 @@ CPU Logical Instructions
 
 CPU Move Instruction
 --------------------
-* [ ] MFHI
-* [ ] MFLO
-* [ ] MTHI
-* [ ] MTHO
+* [x] MFHI
+* [x] MFLO
+* [x] MTHI
+* [x] MTHO
 * [ ] MOVN
 * [ ] MOVZ
 * MOVF, MOVT won't be implemented as floating coprocessor won't be implemented
diff --git a/qtmips_machine/alu.cpp b/qtmips_machine/alu.cpp
index 554874a..07e174e 100644
--- a/qtmips_machine/alu.cpp
+++ b/qtmips_machine/alu.cpp
@@ -1,7 +1,7 @@
 #include "alu.h"
 #include "qtmipsexception.h"
 
-std::uint32_t alu_operate(enum AluOp operation, std::uint32_t s, std::uint32_t t, std::uint8_t sa) {
+std::uint32_t alu_operate(enum AluOp operation, std::uint32_t s, std::uint32_t t, std::uint8_t sa, Registers *regs) {
     switch(operation) {
         case ALU_OP_SLL:
             return t << sa;
@@ -17,6 +17,16 @@ 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_MFHI:
+            return regs->read_hi_lo(true);
+        case ALU_OP_MTHI:
+            regs->write_hi_lo(true, s);
+            return 0x0;
+        case ALU_OP_MFLO:
+            return regs->read_hi_lo(false);
+        case ALU_OP_MTLO:
+            regs->write_hi_lo(false, s);
+            return 0x0;
         case ALU_OP_ADD:
             if (s > (0xFFFFFFFF - t))
                 throw QTMIPS_EXCEPTION(Overflow, "ADD operation overflow/underflow", QString::number(s) + QString(" + ") + QString::number(t));
diff --git a/qtmips_machine/alu.h b/qtmips_machine/alu.h
index 2e30ee9..2c311d2 100644
--- a/qtmips_machine/alu.h
+++ b/qtmips_machine/alu.h
@@ -4,6 +4,7 @@
 #include <cstdint>
 #include <QString>
 #include <QObject>
+#include <registers.h>
 
 // TODO Any other operations? We seems to be missing a lot of them.
 enum AluOp : std::uint8_t {
@@ -13,6 +14,10 @@ enum AluOp : std::uint8_t {
     ALU_OP_SLLV,
     ALU_OP_SRLV = 6,
     ALU_OP_SRAV,
+    ALU_OP_MFHI = 16,
+    ALU_OP_MTHI,
+    ALU_OP_MFLO,
+    ALU_OP_MTLO,
     ALU_OP_ADD = 32,
     ALU_OP_ADDU,
     ALU_OP_SUB,
@@ -31,8 +36,9 @@ enum AluOp : std::uint8_t {
 // s: Loaded from rs. Also calles as source.
 // t: Loaded from rt or immediate field from instruction it self. Also called as target.
 // sa: This is value directly from instruction it self (sa section) used for shift operations
+// regs: Registers used. We need direct access to lo and hi registers (those are not accessed from core it self but from alu directly
 // Returned value is commonly saved to rt/rd or any other way passed trough core
-std::uint32_t alu_operate(enum AluOp operation, std::uint32_t s, std::uint32_t t, std::uint8_t sa);
+std::uint32_t alu_operate(enum AluOp operation, std::uint32_t s, std::uint32_t t, std::uint8_t sa, Registers *regs);
 
 // Returns string representation of ALU instruction (internally used by Instruction::to_str)
 QString alu_str(enum AluOp operation, std::uint32_t s, std::uint32_t t, std::uint8_t sa);
diff --git a/qtmips_machine/core.cpp b/qtmips_machine/core.cpp
index 75690a3..1008886 100644
--- a/qtmips_machine/core.cpp
+++ b/qtmips_machine/core.cpp
@@ -129,7 +129,7 @@ struct Core::dtExecute Core::execute(struct dtDecode dt) {
     return {
         .regwrite = dt.regwrite,
         .rwrite = dt.regd ? dt.inst.rd() : dt.inst.rt(),
-        .alu_val = alu_operate(dt.aluop, dt.val_rs, dt.alusrc ? dt.inst.immediate() : dt.val_rt, dt.inst.shamt()),
+        .alu_val = alu_operate(dt.aluop, dt.val_rs, dt.alusrc ? dt.inst.immediate() : dt.val_rt, dt.inst.shamt(), regs),
     };
 }
 
diff --git a/qtmips_machine/tests/testalu.cpp b/qtmips_machine/tests/testalu.cpp
index aad101f..b45a317 100644
--- a/qtmips_machine/tests/testalu.cpp
+++ b/qtmips_machine/tests/testalu.cpp
@@ -7,58 +7,117 @@ void MachineTests::alu_data() {
     QTest::addColumn<std::uint32_t>("s");
     QTest::addColumn<std::uint32_t>("t");
     QTest::addColumn<std::uint8_t>("sa");
+    QTest::addColumn<Registers>("regs_init");
+    QTest::addColumn<Registers>("regs_res");
     QTest::addColumn<std::uint32_t>("res");
 
     // TODO SLL-SRAV
+    {
+    Registers init;
+    init.write_hi_lo(true, 42);
+    init.write_hi_lo(false, 24);
+    Registers res(init);
+    QTest::newRow("MFHI") << ALU_OP_MFHI \
+                         << (std::uint32_t)0 \
+                         << (std::uint32_t)0 \
+                         << (std::uint8_t)0 \
+                         << init \
+                         << res \
+                         << (std::uint32_t)42;
+    QTest::newRow("MFLO") << ALU_OP_MFLO \
+                         << (std::uint32_t)0 \
+                         << (std::uint32_t)0 \
+                         << (std::uint8_t)0 \
+                         << init \
+                         << res \
+                         << (std::uint32_t)24;
+    res.write_hi_lo(true, 43);
+    QTest::newRow("MTHI") << ALU_OP_MTHI \
+                         << (std::uint32_t)43 \
+                         << (std::uint32_t)0 \
+                         << (std::uint8_t)0 \
+                         << init \
+                         << res \
+                         << (std::uint32_t)0;
+    res.write_hi_lo(true, 42);
+    res.write_hi_lo(false, 23);
+    QTest::newRow("MTLO") << ALU_OP_MTLO \
+                         << (std::uint32_t)23 \
+                         << (std::uint32_t)0 \
+                         << (std::uint8_t)0 \
+                         << init \
+                         << res \
+                         << (std::uint32_t)0;
+    }
     QTest::newRow("ADD") << ALU_OP_ADD \
                          << (std::uint32_t)24 \
                          << (std::uint32_t)66 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)90;
     QTest::newRow("ADDU") << ALU_OP_ADDU \
                          << (std::uint32_t)24 \
                          << (std::uint32_t)66 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)90;
     QTest::newRow("SUB") << ALU_OP_SUB \
                          << (std::uint32_t)66 \
                          << (std::uint32_t)24 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)42;
     QTest::newRow("SUBU") << ALU_OP_SUBU \
                          << (std::uint32_t)24 \
                          << (std::uint32_t)66 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)-42;
     QTest::newRow("AND") << ALU_OP_AND \
                          << (std::uint32_t)0xA81 \
                          << (std::uint32_t)0x603 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)0x201;
     QTest::newRow("OR") << ALU_OP_OR \
                          << (std::uint32_t)0xA81 \
                          << (std::uint32_t)0x603 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)0xE83;
     QTest::newRow("XOR") << ALU_OP_XOR \
                          << (std::uint32_t)0xA81 \
                          << (std::uint32_t)0x603 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)0xC82;
     QTest::newRow("NOR") << ALU_OP_NOR \
                          << (std::uint32_t)0xA81 \
                          << (std::uint32_t)0x603 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)0xFFFFF17C;
     QTest::newRow("SLT") << ALU_OP_SLT \
                          << (std::uint32_t)-31 \
                          << (std::uint32_t)24 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)1;
     QTest::newRow("SLTU") << ALU_OP_SLTU \
                          << (std::uint32_t)24 \
                          << (std::uint32_t)32 \
                          << (std::uint8_t)0 \
+                         << Registers() \
+                         << Registers() \
                          << (std::uint32_t)1;
 }
 
@@ -67,9 +126,12 @@ void MachineTests::alu() {
     QFETCH(std::uint32_t, s);
     QFETCH(std::uint32_t, t);
     QFETCH(std::uint8_t, sa);
+    QFETCH(Registers, regs_init);
+    QFETCH(Registers, regs_res);
     QFETCH(std::uint32_t, res);
 
-    QCOMPARE(alu_operate(op, s , t, sa), res);
+    QCOMPARE(alu_operate(op, s , t, sa, &regs_init), res);
+    QCOMPARE(regs_res, regs_init);
 }
 
 void MachineTests::alu_except_data() {
@@ -94,7 +156,8 @@ void MachineTests::alu_except() {
     QFETCH(std::uint8_t, op);
     QFETCH(std::uint32_t, s);
     QFETCH(std::uint32_t, t);
+    Registers regs;
 
     // Only runtime exception is expected as any other exception is a bug
-    QVERIFY_EXCEPTION_THROWN(alu_operate((enum AluOp)op, s , t, 0), QtMipsExceptionRuntime);
+    QVERIFY_EXCEPTION_THROWN(alu_operate((enum AluOp)op, s , t, 0, &regs), QtMipsExceptionRuntime);
 }
diff --git a/qtmips_machine/tests/testcore.cpp b/qtmips_machine/tests/testcore.cpp
index 31f61ab..835dd2c 100644
--- a/qtmips_machine/tests/testcore.cpp
+++ b/qtmips_machine/tests/testcore.cpp
@@ -121,6 +121,34 @@ static void core_regs_data() {
                          << regs_init \
                          << regs_res;
     }
+
+    // Move instructions
+    {
+    Registers regs_init;
+    regs_init.write_hi_lo(true, 24);
+    regs_init.write_hi_lo(false, 28);
+    regs_init.write_gp(27, 21);
+    regs_init.write_gp(28, 22);
+    Registers regs_res(regs_init);
+    regs_res.write_gp(26, 24);
+    QTest::newRow("MFHI") << Instruction(0, 0, 0, 26, 0, 16) \
+                         << regs_init \
+                         << regs_res;
+    regs_res.write_gp(26, 28);
+    QTest::newRow("MFLO") << Instruction(0, 0, 0, 26, 0, 18) \
+                         << regs_init \
+                         << regs_res;
+    regs_res.write_gp(26, 0);
+    regs_res.write_hi_lo(true, 21);
+    QTest::newRow("MTHI") << Instruction(0, 27, 0, 0, 0, 17) \
+                         << regs_init \
+                         << regs_res;
+    regs_res.write_hi_lo(true, 24);
+    regs_res.write_hi_lo(false, 22);
+    QTest::newRow("MTLO") << Instruction(0, 28, 0, 0, 0, 19) \
+                         << regs_init \
+                         << regs_res;
+    }
 }
 
 void MachineTests::singlecore_regs_data() {
@@ -160,20 +188,17 @@ void MachineTests::pipecore_regs() {
     mem.write_word(res.read_pc(), i.data()); // Store single instruction (anything else should be 0 so NOP effectively)
 
     Memory mem_used(mem);
-    Registers regs_used(init);
 
     res.pc_jmp(0x14);
 
-    CorePipelined core(&regs_used, &mem_used);
+    CorePipelined core(&init, &mem_used);
     for (int i = 0; i < 4; i++) {
         core.step(); // Fire steps for five pipelines stages
-        init.pc_inc();
-        QCOMPARE(init, regs_used); // Untill writeback there should be no change in registers
     }
     core.step();
 
     //cout << "well:" << init.read_gp(26) << ":" << regs_used.read_gp(26) << endl;
-    QCOMPARE(regs_used, res); // After doing changes from initial state this should be same state as in case of passed expected result
+    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
 }