Build constants using instructions mov/orr or mvn/eor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33141 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMCommon.cpp b/lib/Target/ARM/ARMCommon.cpp
new file mode 100644
index 0000000..fd37573
--- /dev/null
+++ b/lib/Target/ARM/ARMCommon.cpp
@@ -0,0 +1,84 @@
+//===-- ARMCommon.cpp - Define support functions for ARM --------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by the "Instituto Nokia de Tecnologia" and
+// is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//
+//
+//===----------------------------------------------------------------------===//
+#include "ARMCommon.h"
+
+static inline unsigned rotateL(unsigned x, unsigned n){
+ return ((x << n) | (x >> (32 - n)));
+}
+
+static inline unsigned rotateR(unsigned x, unsigned n){
+ return ((x >> n) | (x << (32 - n)));
+}
+
+// finds the end position of largest sequence of zeros in binary representation
+// of 'immediate'.
+static int findLargestZeroSequence(unsigned immediate){
+ int max_zero_pos = 0;
+ int max_zero_length = 0;
+ int zero_pos;
+ int zero_length;
+ int pos = 0;
+ int end_pos;
+
+ while ((immediate & 0x3) == 0) {
+ immediate = rotateR(immediate, 2);
+ pos+=2;
+ }
+ end_pos = pos+32;
+
+ while (pos<end_pos){
+ while (((immediate & 0x3) != 0)&&(pos<end_pos)) {
+ immediate = rotateR(immediate, 2);
+ pos+=2;
+ }
+ zero_pos = pos;
+ while (((immediate & 0x3) == 0)&&(pos<end_pos)) {
+ immediate = rotateR(immediate, 2);
+ pos+=2;
+ }
+ zero_length = pos - zero_pos;
+ if (zero_length > max_zero_length){
+ max_zero_length = zero_length;
+ max_zero_pos = zero_pos % 32;
+ }
+
+ }
+
+ return (max_zero_pos + max_zero_length) % 32;
+}
+
+std::vector<unsigned> splitImmediate(unsigned immediate){
+ std::vector<unsigned> immediatePieces;
+
+ if (immediate == 0){
+ immediatePieces.push_back(0);
+ } else {
+ int start_pos = findLargestZeroSequence(immediate);
+ unsigned immediate_tmp = rotateR(immediate, start_pos);
+ int pos = 0;
+ while (pos < 32){
+ while(((immediate_tmp&0x3) == 0)&&(pos<32)){
+ immediate_tmp = rotateR(immediate_tmp,2);
+ pos+=2;
+ }
+ if (pos < 32){
+ immediatePieces.push_back(rotateL(immediate_tmp&0xFF,
+ (start_pos + pos) % 32 ));
+ immediate_tmp = rotateR(immediate_tmp,8);
+ pos+=8;
+ }
+ }
+ }
+ return immediatePieces;
+}