From 83fe874dcc7fca810ca0aa1ddc2eadd93deae0b3 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 9 Nov 2013 01:34:42 -0800
Subject: [PATCH] armjit: Use multiple BICs in ANDI2R if possible.

Rather than a temporary.
---
 Common/ArmEmitter.cpp | 38 +++++++++++++++++++++++++++++++++++---
 1 file changed, 35 insertions(+), 3 deletions(-)

diff --git a/Common/ArmEmitter.cpp b/Common/ArmEmitter.cpp
index cfde87102a..337e8f7b81 100644
--- a/Common/ArmEmitter.cpp
+++ b/Common/ArmEmitter.cpp
@@ -177,15 +177,47 @@ void ARMXEmitter::ANDI2R(ARMReg rd, ARMReg rs, u32 val, ARMReg scratch)
 {
 	Operand2 op2;
 	bool inverse;
-	if (TryMakeOperand2_AllowInverse(val, op2, &inverse)) {
+	if (val == 0) {
+		// Avoid the ALU, may improve pipeline.
+		MOV(rd, 0);
+	} else if (TryMakeOperand2_AllowInverse(val, op2, &inverse)) {
 		if (!inverse) {
 			AND(rd, rs, op2);
 		} else {
 			BIC(rd, rs, op2);
 		}
 	} else {
-		MOVI2R(scratch, val);
-		AND(rd, rs, scratch);
+		int ops = 0;
+		for (int i = 0; i < 32; i += 2) {
+			u8 bits = (val >> i) & 0xFF;
+			// If either low bit is not set, we need to use a BIC for them.
+			if ((bits & 3) != 3) {
+				++ops;
+				i += 8 - 2;
+			}
+		}
+
+		// The worst case is 4 (e.g. 0x55555555.)
+		if (ops <= 3) {
+			bool first = true;
+			for (int i = 0; i < 32; i += 2) {
+				u8 bits = (val >> i) & 0xFF;
+				if ((bits & 3) != 3) {
+					u8 rotation = i == 0 ? 0 : 16 - i / 2;
+					if (first) {
+						BIC(rd, rs, Operand2(~bits, rotation));
+						first = false;
+					} else {
+						BIC(rd, rd, Operand2(~bits, rotation));
+					}
+					// Well, we took care of these other bits while we were at it.
+					i += 8 - 2;
+				}
+			}
+		} else {
+			MOVI2R(scratch, val);
+			AND(rd, rs, scratch);
+		}
 	}
 }