zba/src/cpu/thumb/format14.zig

51 lines
1.5 KiB
Zig

const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
pub fn format14(comptime L: bool, comptime R: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
var address: u32 = undefined;
if (L) {
// POP
address = cpu.r[13];
var i: usize = 0;
while (i < 8) : (i += 1) {
if ((opcode >> @truncate(u3, i)) & 1 == 1) {
cpu.r[i] = bus.read32(address);
address += 4;
}
}
if (R) {
const value = bus.read32(address);
cpu.r[15] = value & 0xFFFF_FFFE;
address += 4;
}
} else {
address = cpu.r[13] - 4;
if (R) {
bus.write32(address, cpu.r[14]);
address -= 4;
}
var i: usize = 8;
while (i > 0) : (i -= 1) {
const j = i - 1;
if ((opcode >> @truncate(u3, j)) & 1 == 1) {
bus.write32(address, cpu.r[j]);
address -= 4;
}
}
}
cpu.r[13] = address + if (!L) 4 else 0;
}
}.inner;
}