From 0d7da86ea5e5187dca2e843549c33f761e35f068 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= Date: Sat, 25 Nov 2017 16:39:10 +0100 Subject: Add crude implementation of MOV* instructions I don't like how it's implemented but I have no other idea atm. --- instructions.md | 4 ++-- qtmips_machine/alu.cpp | 6 ++++++ qtmips_machine/alu.h | 2 ++ qtmips_machine/core.cpp | 8 +++++++- qtmips_machine/tests/testalu.cpp | 14 ++++++++++++++ qtmips_machine/tests/testcore.cpp | 16 ++++++++++++++++ 6 files changed, 47 insertions(+), 3 deletions(-) diff --git a/instructions.md b/instructions.md index 7682226..87d4dd5 100644 --- a/instructions.md +++ b/instructions.md @@ -90,8 +90,8 @@ CPU Move Instruction * [x] MFLO * [x] MTHI * [x] MTHO -* [ ] MOVN -* [ ] MOVZ +* [x] MOVN +* [x] MOVZ * MOVF, MOVT won't be implemented as floating coprocessor won't be implemented CPU Shift Instructions diff --git a/qtmips_machine/alu.cpp b/qtmips_machine/alu.cpp index 07e174e..8be9f2a 100644 --- a/qtmips_machine/alu.cpp +++ b/qtmips_machine/alu.cpp @@ -17,6 +17,12 @@ 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_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; + case ALU_OP_MOVN: + // Same note as for MOVZ applies here + return t != 0 ? s : 0; case ALU_OP_MFHI: return regs->read_hi_lo(true); case ALU_OP_MTHI: diff --git a/qtmips_machine/alu.h b/qtmips_machine/alu.h index 2c311d2..4818bb1 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_MOVZ = 10, + ALU_OP_MOVN, ALU_OP_MFHI = 16, ALU_OP_MTHI, ALU_OP_MFLO, diff --git a/qtmips_machine/core.cpp b/qtmips_machine/core.cpp index 1008886..20c1b74 100644 --- a/qtmips_machine/core.cpp +++ b/qtmips_machine/core.cpp @@ -126,8 +126,14 @@ struct Core::dtDecode Core::decode(struct dtFetch dt) { struct Core::dtExecute Core::execute(struct dtDecode dt) { // TODO signals + // Handle conditional move (we have to change regwrite signal if conditional is not met) + // TODO can't we do this some cleaner way? + bool regwrite = dt.regwrite; + if (dt.inst.opcode() == 0 && ((dt.inst.funct() == 10 && dt.val_rt != 0) || (dt.inst.funct() == 11 && dt.val_rt == 0))) + regwrite = false; + return { - .regwrite = dt.regwrite, + .regwrite = 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(), regs), }; diff --git a/qtmips_machine/tests/testalu.cpp b/qtmips_machine/tests/testalu.cpp index b45a317..603a610 100644 --- a/qtmips_machine/tests/testalu.cpp +++ b/qtmips_machine/tests/testalu.cpp @@ -12,6 +12,20 @@ void MachineTests::alu_data() { QTest::addColumn("res"); // TODO SLL-SRAV + QTest::newRow("MOVZ") << ALU_OP_MOVZ \ + << (std::uint32_t)22 \ + << (std::uint32_t)0 \ + << (std::uint8_t)0 \ + << Registers() \ + << Registers() \ + << (std::uint32_t)22; + QTest::newRow("MOVN") << ALU_OP_MOVN \ + << (std::uint32_t)22 \ + << (std::uint32_t)1 \ + << (std::uint8_t)0 \ + << Registers() \ + << Registers() \ + << (std::uint32_t)22; { Registers init; init.write_hi_lo(true, 42); diff --git a/qtmips_machine/tests/testcore.cpp b/qtmips_machine/tests/testcore.cpp index 835dd2c..27a49b4 100644 --- a/qtmips_machine/tests/testcore.cpp +++ b/qtmips_machine/tests/testcore.cpp @@ -127,6 +127,8 @@ static void core_regs_data() { Registers regs_init; regs_init.write_hi_lo(true, 24); regs_init.write_hi_lo(false, 28); + regs_init.write_gp(24, 55); + regs_init.write_gp(25, 56); regs_init.write_gp(27, 21); regs_init.write_gp(28, 22); Registers regs_res(regs_init); @@ -148,6 +150,20 @@ static void core_regs_data() { QTest::newRow("MTLO") << Instruction(0, 28, 0, 0, 0, 19) \ << regs_init \ << regs_res; + regs_res.write_hi_lo(false, 28); + QTest::newRow("MOVZ-F") << Instruction(0, 24, 24, 25, 0, 10) \ + << regs_init \ + << regs_res; + QTest::newRow("MOVN-F") << Instruction(0, 24, 1, 25, 0, 11) \ + << regs_init \ + << regs_res; + regs_res.write_gp(25, 55); + QTest::newRow("MOVZ-T") << Instruction(0, 24, 1, 25, 0, 10) \ + << regs_init \ + << regs_res; + QTest::newRow("MOVN-T") << Instruction(0, 24, 24, 25, 0, 11) \ + << regs_init \ + << regs_res; } } -- cgit v1.2.3