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fix: improve perf of instructions w/ rotr

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This commit is contained in:
Rekai Nyangadzayi Musuka
2022-03-16 22:28:24 -03:00
parent 1921218c7b
commit 39ab363afa
7 changed files with 33 additions and 13 deletions
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4
src/cpu/arm/single_data_swap.zig
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@@ -4,6 +4,8 @@ const Bus = @import("../../Bus.zig");
const Arm7tdmi = @import("../../cpu.zig").Arm7tdmi;
const InstrFn = @import("../../cpu.zig").ArmInstrFn;
const rotr = @import("../../util.zig").rotr;
pub fn singleDataSwap(comptime B: bool) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u32) void {
@@ -20,7 +22,7 @@ pub fn singleDataSwap(comptime B: bool) InstrFn {
cpu.r[rd] = value;
} else {
// SWP
const value = std.math.rotr(u32, bus.read32(address & 0xFFFF_FFFC), 8 * (address & 0x3));
const value = rotr(u32, bus.read32(address & 0xFFFF_FFFC), 8 * (address & 0x3));
bus.write32(address & 0xFFFF_FFFC, cpu.r[rm]);
cpu.r[rd] = value;
}