paoda/zba
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

feat: move thumb instr decoding to module

Browse Source
This commit is contained in:
Rekai Nyangadzayi Musuka
2022-07-27 13:10:58 -03:00
parent 53191b0eeb
commit 9d037fdc3e
8 changed files with 169 additions and 186 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
src/core/cpu/thumb/data_processing.zig
View File

@@ -2,7 +2,7 @@ const std = @import("std");
const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ThumbInstrFn;
const InstrFn = @import("../../cpu.zig").thumb.InstrFn;
const shifter = @import("../barrel_shifter.zig");
const add = @import("../arm/data_processing.zig").add;
@@ -12,7 +12,7 @@ const setLogicOpFlags = @import("../arm/data_processing.zig").setLogicOpFlags;
const log = std.log.scoped(.Thumb1);
pub fn format1(comptime op: u2, comptime offset: u5) InstrFn {
pub fn fmt1(comptime op: u2, comptime offset: u5) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const rs = opcode >> 3 & 0x7;
@@ -55,7 +55,37 @@ pub fn format1(comptime op: u2, comptime offset: u5) InstrFn {
}.inner;
}
pub fn format2(comptime I: bool, is_sub: bool, rn: u3) InstrFn {
pub fn fmt5(comptime op: u2, comptime h1: u1, comptime h2: u1) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const src_idx = @as(u4, h2) << 3 | (opcode >> 3 & 0x7);
const dst_idx = @as(u4, h1) << 3 | (opcode & 0x7);
const src = if (src_idx == 0xF) (cpu.r[src_idx] + 2) & 0xFFFF_FFFE else cpu.r[src_idx];
const dst = if (dst_idx == 0xF) (cpu.r[dst_idx] + 2) & 0xFFFF_FFFE else cpu.r[dst_idx];
switch (op) {
0b00 => {
// ADD
const sum = add(false, cpu, dst, src);
cpu.r[dst_idx] = if (dst_idx == 0xF) sum & 0xFFFF_FFFE else sum;
},
0b01 => cmp(cpu, dst, src), // CMP
0b10 => {
// MOV
cpu.r[dst_idx] = if (dst_idx == 0xF) src & 0xFFFF_FFFE else src;
},
0b11 => {
// BX
cpu.cpsr.t.write(src & 1 == 1);
cpu.r[15] = src & 0xFFFF_FFFE;
},
}
}
}.inner;
}
pub fn fmt2(comptime I: bool, is_sub: bool, rn: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const rs = opcode >> 3 & 0x7;
@@ -80,7 +110,7 @@ pub fn format2(comptime I: bool, is_sub: bool, rn: u3) InstrFn {
}.inner;
}
pub fn format3(comptime op: u2, comptime rd: u3) InstrFn {
pub fn fmt3(comptime op: u2, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
const offset = @truncate(u8, opcode);
@@ -99,7 +129,7 @@ pub fn format3(comptime op: u2, comptime rd: u3) InstrFn {
}.inner;
}
pub fn format12(comptime isSP: bool, comptime rd: u3) InstrFn {
pub fn fmt12(comptime isSP: bool, comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// ADD
@@ -111,7 +141,7 @@ pub fn format12(comptime isSP: bool, comptime rd: u3) InstrFn {
}.inner;
}
pub fn format13(comptime S: bool) InstrFn {
pub fn fmt13(comptime S: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, _: *Bus, opcode: u16) void {
// ADD