101 lines
2.8 KiB
Zig
101 lines
2.8 KiB
Zig
const Bus = @import("../../Bus.zig");
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const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
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const InstrFn = @import("../../cpu.zig").thumb.InstrFn;
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pub fn fmt14(comptime L: bool, comptime R: bool) InstrFn {
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return struct {
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fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
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const count = @boolToInt(R) + countRlist(opcode);
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const start = cpu.r[13] - if (!L) count * 4 else 0;
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var end = cpu.r[13];
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if (L) {
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end += count * 4;
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} else {
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end -= 4;
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}
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var address = start;
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var i: u4 = 0;
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while (i < 8) : (i += 1) {
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if (opcode >> i & 1 == 1) {
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if (L) {
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cpu.r[i] = bus.read(u32, address);
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} else {
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bus.write(u32, address, cpu.r[i]);
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}
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address += 4;
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}
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}
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if (R) {
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if (L) {
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const value = bus.read(u32, address);
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cpu.r[15] = value & ~@as(u32, 1);
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cpu.pipe.reload(cpu);
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} else {
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bus.write(u32, address, cpu.r[14]);
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}
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address += 4;
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}
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cpu.r[13] = if (L) end else start;
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}
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}.inner;
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}
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pub fn fmt15(comptime L: bool, comptime rb: u3) InstrFn {
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return struct {
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fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
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var address = cpu.r[rb];
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const end_address = cpu.r[rb] + 4 * countRlist(opcode);
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if (opcode & 0xFF == 0) {
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if (L) {
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cpu.r[15] = bus.read(u32, address);
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cpu.pipe.reload(cpu);
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} else {
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bus.write(u32, address, cpu.r[15] + 2);
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}
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cpu.r[rb] += 0x40;
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return;
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}
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var i: u4 = 0;
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var first_write = true;
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while (i < 8) : (i += 1) {
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if (opcode >> i & 1 == 1) {
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if (L) {
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cpu.r[i] = bus.read(u32, address);
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} else {
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bus.write(u32, address, cpu.r[i]);
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}
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if (!L and first_write) {
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cpu.r[rb] = end_address;
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first_write = false;
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}
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address += 4;
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}
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}
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if (L and opcode >> rb & 1 != 1) cpu.r[rb] = address;
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}
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}.inner;
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}
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inline fn countRlist(opcode: u16) u32 {
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var count: u32 = 0;
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inline for (0..8) |i| {
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if (opcode >> (7 - i) & 1 == 1) count += 1;
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}
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return count;
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}
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