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

chore: refactor instruction exec code

Browse Source
This commit is contained in:
Rekai Nyangadzayi Musuka
2022-01-07 19:44:48 -04:00
parent a407671de2
commit f8c6af3247
5 changed files with 37 additions and 29 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
src/cpu.zig
View File

@@ -9,9 +9,10 @@ const Scheduler = @import("scheduler.zig").Scheduler;
const Bitfield = bitfield.Bitfield;
const Bit = bitfield.Bit;
const comptimeDataProcessing = @import("cpu/data_processing.zig").comptimeDataProcessing;
const comptimeSingleDataTransfer = @import("cpu/single_data_transfer.zig").comptimeSingleDataTransfer;
const comptimeHalfSignedDataTransfer = @import("cpu/half_signed_data_transfer.zig").comptimeHalfSignedDataTransfer;
const dataProcessing = @import("cpu/data_processing.zig").dataProcessing;
const singleDataTransfer = @import("cpu/single_data_transfer.zig").singleDataTransfer;
const halfAndSignedDataTransfer = @import("cpu/half_signed_data_transfer.zig").halfAndSignedDataTransfer;
const branch = @import("cpu/branch.zig").branch;
pub const InstrFn = fn (*Arm7tdmi, *Bus, u32) void;
const arm_lut: [0x1000]InstrFn = populate();
@@ -58,7 +59,7 @@ pub const Arm7tdmi = struct {
return word;
}
fn fakePC(self: *const @This()) u32 {
pub fn fakePC(self: *const @This()) u32 {
return self.r[15] + 4;
}
@@ -128,7 +129,7 @@ fn populate() [0x1000]InstrFn {
const S = i >> 4 & 1 == 1;
const instrKind = i >> 5 & 0xF;
lut[i] = comptimeDataProcessing(I, S, instrKind);
lut[i] = dataProcessing(I, S, instrKind);
}
if (i >> 9 & 0x7 == 0b000 and i >> 3 & 1 == 1 and i & 1 == 1) {
@@ -138,7 +139,7 @@ fn populate() [0x1000]InstrFn {
const W = i >> 5 & 1 == 1;
const L = i >> 4 & 1 == 1;
lut[i] = comptimeHalfSignedDataTransfer(P, U, I, W, L);
lut[i] = halfAndSignedDataTransfer(P, U, I, W, L);
}
if (i >> 10 & 0x3 == 0b01) {
@@ -149,12 +150,12 @@ fn populate() [0x1000]InstrFn {
const W = i >> 5 & 1 == 1;
const L = i >> 4 & 1 == 1;
lut[i] = comptimeSingleDataTransfer(I, P, U, B, W, L);
lut[i] = singleDataTransfer(I, P, U, B, W, L);
}
if (i >> 9 & 0x7 == 0b101) {
const L = i >> 8 & 1 == 1;
lut[i] = comptimeBranch(L);
lut[i] = branch(L);
}
}
@@ -188,15 +189,3 @@ fn undefinedInstruction(_: *Arm7tdmi, _: *Bus, opcode: u32) void {
const id = armIdx(opcode);
std.debug.panic("[CPU] {{0x{X:}}} 0x{X:} is an illegal opcode", .{ id, opcode });
}
fn comptimeBranch(comptime L: bool) InstrFn {
return struct {
fn branch(cpu: *Arm7tdmi, _: *Bus, opcode: u32) void {
if (L) {
cpu.r[14] = cpu.r[15] - 4;
}
cpu.r[15] = cpu.fakePC() +% util.u32SignExtend(24, opcode << 2);
}
}.branch;
}