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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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14
src/cpu/thumb/data_transfer.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").ThumbInstrFn;
const rotr = @import("../../util.zig").rotr;
pub fn format6(comptime rd: u3) InstrFn {
return struct {
fn inner(cpu: *Arm7tdmi, bus: *Bus, opcode: u16) void {
@@ -39,7 +41,7 @@ pub fn format78(comptime op: u2, comptime T: bool) InstrFn {
0b10 => {
// LDRH
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 1));
cpu.r[rd] = rotr(u32, value, 8 * (address & 1));
},
0b11 => {
// LDRSH
@@ -49,7 +51,7 @@ pub fn format78(comptime op: u2, comptime T: bool) InstrFn {
break :blk sext(16, bus.read16(address));
};
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 1));
cpu.r[rd] = rotr(u32, value, 8 * (address & 1));
},
}
} else {
@@ -66,7 +68,7 @@ pub fn format78(comptime op: u2, comptime T: bool) InstrFn {
0b10 => {
// LDR
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
cpu.r[rd] = rotr(u32, value, 8 * (address & 0x3));
},
0b11 => {
// LDRB
@@ -93,7 +95,7 @@ pub fn format9(comptime B: bool, comptime L: bool, comptime offset: u5) InstrFn
// LDR
const address = cpu.r[rb] + (@as(u32, offset) << 2);
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
cpu.r[rd] = rotr(u32, value, 8 * (address & 0x3));
}
} else {
if (B) {
@@ -121,7 +123,7 @@ pub fn format10(comptime L: bool, comptime offset: u5) InstrFn {
if (L) {
// LDRH
const value = bus.read16(address & 0xFFFF_FFFE);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 1));
cpu.r[rd] = rotr(u32, value, 8 * (address & 1));
} else {
// STRH
bus.write16(address & 0xFFFF_FFFE, @truncate(u16, cpu.r[rd]));
@@ -139,7 +141,7 @@ pub fn format11(comptime L: bool, comptime rd: u3) InstrFn {
if (L) {
// LDR
const value = bus.read32(address & 0xFFFF_FFFC);
cpu.r[rd] = std.math.rotr(u32, value, 8 * (address & 0x3));
cpu.r[rd] = rotr(u32, value, 8 * (address & 0x3));
} else {
// STR
bus.write32(address & 0xFFFF_FFFC, cpu.r[rd]);