Merge pull request #77 from matheusgomes28/nop-support

NOP support and tests
matheusgomes28 · Oct 17, 2024 · 8bf0318 · 8bf0318
2 parents b81ba75 + 00bad58
commit 8bf0318
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Showing 4 changed files with 58 additions and 6 deletions.
diff --git a/README.md b/README.md
@@ -311,23 +311,23 @@ Total number of `ROL` instructions: `5`.
 
 Total number of `CMP` instructions: `8`.
 
-### CPX - Compare Memory with Accumulator
+### CPX - Compare Memory with X Register
 
 | **Opcode** | **Addressing Mode** | **Opcode (Hex)** | **Bytes** | **Cycles** | **Supported**      |
 |------------|---------------------|------------------|-----------|------------|--------------------|
 | CPX        | Immediate           | 0xE0             | 2         | 2          | :white_check_mark: |
 | CPX        | Zero Page           | 0xE4             | 2         | 3          | :white_check_mark: |
-| CPX        | Absolute            | 0xEC             | 3         | 4          | :ok:               |
+| CPX        | Absolute            | 0xEC             | 3         | 4          | :white_check_mark: |
 
 Total number of `CPX` instructions: `3`.
 
-### CPY - Compare Memory with Accumulator
+### CPY - Compare Memory with Y Register
 
 | **Opcode** | **Addressing Mode** | **Opcode (Hex)** | **Bytes** | **Cycles** | **Supported**      |
 |------------|---------------------|------------------|-----------|------------|--------------------|
 | CPY        | Immediate           | 0xC0             | 2         | 2          | :white_check_mark: |
 | CPY        | Zero Page           | 0xC4             | 2         | 3          | :white_check_mark: |
-| CPY        | Absolute            | 0xCC             | 3         | 4          | :ok:               |
+| CPY        | Absolute            | 0xCC             | 3         | 4          | :white_check_mark: |
 
 Total number of `CPY` instructions: `3`.
 
@@ -386,7 +386,7 @@ total number of interrupt instructions: `2`.
 |------------|---------------------|------------------|-----------|------------|--------------------|
 | BIT        | Zeropage            | 0x24             | 2         | 3          | :x:                |
 | BIT        | Absolute            | 0x2c             | 3         | 4          | :x:                |
-| NOP        | Implied             | 0xEA             | 1         | 2          | :x:                |
+| NOP        | Implied             | 0xEA             | 1         | 2          | :white_check_mark: |
 
 total number of random instructions: `2`.
 

diff --git a/emulator/emulator.cpp b/emulator/emulator.cpp
@@ -228,6 +228,13 @@ inline std::uint16_t indirect_indexed(emulator::Cpu& cpu, std::uint8_t val)
     return addr;
 }
 
+/* Functions with no context */
+std::optional<InstructionConfig> nop(emulator::Cpu& cpu, std::span<const std::uint8_t> program)
+{
+    return std::make_optional<InstructionConfig>(1, 2);
+}
+/* End functions with no context */
+
 /* Stack Related Functions */
 std::optional<InstructionConfig> push_accumulator_to_stack(emulator::Cpu& cpu, std::span<const std::uint8_t> program)
 {
@@ -1097,7 +1104,6 @@ void cmp_operation(emulator::Cpu& cpu, std::uint8_t emulator::Registers::*reg, s
     cpu.flags.c           = (cpu.reg).*reg >= val;
 }
 
-
 /// Compares whichever register was given to the immediate
 /// value in the next address in the program array
 Instruction cmp_immediate_reg(std::uint8_t emulator::Registers::*reg)
@@ -1741,6 +1747,9 @@ std::array<Instruction, 256> get_instructions()
     supported_instructions[0xb8] = clear_flag(&emulator::Flags::v);
     supported_instructions[0xd8] = clear_flag(&emulator::Flags::d);
 
+    // Opcodes with no context
+    supported_instructions[0xea] = nop;
+
     return supported_instructions;
 }
 

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
@@ -46,6 +46,7 @@ create_tests(ld_index_indirect_tests)
 create_tests(ld_indirect_indexed_tests)
 create_tests(ld_zeropage_tests)
 create_tests(lsr_tests)
+create_tests(nop_tests)
 create_tests(ora_absolute_indexed_tests)
 create_tests(ora_absolute_tests)
 create_tests(ora_immediate_tests)

diff --git a/tests/nop_tests.cpp b/tests/nop_tests.cpp
@@ -0,0 +1,42 @@
+import emulator;
+
+#include "common.h"
+
+#include <gtest/gtest.h>
+
+#include <array>
+#include <cstdint>
+
+// NOLINTNEXTLINE
+TEST(NOPTests, VeryBoringTests)
+{
+    constexpr std::array<std::uint8_t, 1> program{0xea};
+
+    emulator::Cpu cpu;
+    ASSERT_EQ(emulator::execute(cpu, program), 2);
+
+    ASSERT_EQ(cpu.reg.a, 0x00);
+    ASSERT_EQ(cpu.reg.x, 0x00);
+    ASSERT_EQ(cpu.reg.y, 0x00);
+    ASSERT_EQ(cpu.reg.sp, 0xff);
+    ASSERT_EQ(cpu.reg.pc, 0x01);
+
+    ASSERT_EQ(cpu.flags, make_flags(0b0000'0000));
+}
+
+// NOLINTNEXTLINE
+TEST(NOPTests, AnotherVeryBoringTests)
+{
+    constexpr std::array<std::uint8_t, 3> program{0xea, 0xea, 0xea};
+
+    emulator::Cpu cpu;
+    ASSERT_EQ(emulator::execute(cpu, program), 6);
+
+    ASSERT_EQ(cpu.reg.a, 0x00);
+    ASSERT_EQ(cpu.reg.x, 0x00);
+    ASSERT_EQ(cpu.reg.y, 0x00);
+    ASSERT_EQ(cpu.reg.sp, 0xff);
+    ASSERT_EQ(cpu.reg.pc, 0x03);
+
+    ASSERT_EQ(cpu.flags, make_flags(0b0000'0000));
+}