//! Stack-related tests.
const std = @import("std");
const cpu = @import("../cpu.zig");

test "PHA/PLA" {
    var z = cpu.testZes(.{ .rom = &.{
        .{
            0x8000, cpu.assemble(
                \\LDA #$89
                \\PHA
                \\LDA #0
                \\PLA
            ),
        },
    } });
    cpu.run(&z); // Setup A register

    try std.testing.expectEqual(0xfd, z.cpu.sp);
    cpu.run(&z); // PHA
    try std.testing.expectEqual(0xfc, z.cpu.sp);
    try std.testing.expectEqual(0x8003, z.cpu.pc);
    try std.testing.expectEqual(0x89, z.ram[0x1fd]);
    try std.testing.expect(z.cpu.status.negative);
    try std.testing.expect(!z.cpu.status.zero);

    cpu.run(&z); // Reset A register
    try std.testing.expectEqual(0x8005, z.cpu.pc);
    try std.testing.expectEqual(0x00, z.cpu.a);
    try std.testing.expect(!z.cpu.status.negative);
    try std.testing.expect(z.cpu.status.zero);

    cpu.run(&z); // PLA
    try std.testing.expectEqual(0x8006, z.cpu.pc);
    try std.testing.expectEqual(0x89, z.cpu.a);
    try std.testing.expectEqual(0xfd, z.cpu.sp);
    try std.testing.expect(z.cpu.status.negative);
    try std.testing.expect(!z.cpu.status.zero);
}

test "PHP/PLP" {
    var z = cpu.testZes(.{ .rom = &.{
        .{
            0x8000, cpu.assemble(
                \\CLI
                \\SED
                \\LDA #0
                \\PHP
                \\
                \\SEI
                \\CLD
                \\LDA #$ff
                \\PLP
            ),
        },
    } });

    // Prepare flags
    cpu.run(&z); // Clear I
    cpu.run(&z); // Set D
    cpu.run(&z); // Set Z
    try std.testing.expect(!z.cpu.status.negative);
    try std.testing.expect(z.cpu.status.zero);
    try std.testing.expect(z.cpu.status.decimal);
    try std.testing.expect(!z.cpu.status.irq_disabled);

    try std.testing.expectEqual(0xfd, z.cpu.sp);
    cpu.run(&z); // PHP
    try std.testing.expectEqual(0xfc, z.cpu.sp);

    try std.testing.expectEqual(0x8005, z.cpu.pc);
    try std.testing.expectEqual(0b00111010, z.ram[0x1fd]);

    // Reset flags
    cpu.run(&z); // Set I
    cpu.run(&z); // Clear D
    cpu.run(&z); // Clear Z; Set N
    try std.testing.expect(z.cpu.status.negative);
    try std.testing.expect(!z.cpu.status.zero);
    try std.testing.expect(!z.cpu.status.decimal);
    try std.testing.expect(z.cpu.status.irq_disabled);

    try std.testing.expectEqual(0xfc, z.cpu.sp);
    cpu.run(&z); // PLP
    try std.testing.expectEqual(0xfd, z.cpu.sp);

    try std.testing.expectEqual(0x800a, z.cpu.pc);

    // Check if flags are restored
    try std.testing.expect(!z.cpu.status.negative);
    try std.testing.expect(z.cpu.status.zero);
    try std.testing.expect(z.cpu.status.decimal);
    try std.testing.expect(!z.cpu.status.irq_disabled);

    // BRK should not be restored.
    try std.testing.expect(!z.cpu.status.brk);
}