Simplify the use of the stm instruction on ARM.

src/arm/macro-assembler-arm.h

Index: src/arm/macro-assembler-arm.h
===================================================================
--- src/arm/macro-assembler-arm.h	(revision 4499)
+++ src/arm/macro-assembler-arm.h	(working copy)
@@ -93,6 +93,65 @@
   // well as the ip register.
   void RecordWrite(Register object, Register offset, Register scratch);
 
+  // Push two registers.  Pushes leftmost register first (to highest address).
+  void Push(Register src1, Register src2, Condition cond = al) {
+    ASSERT(!src1.is(src2));
+    if (src1.code() > src2.code()) {
+      stm(db_w, sp, src1.bit() | src2.bit(), cond);
+    } else {
+      str(src1, MemOperand(sp, 4, NegPreIndex), cond);

[Søren Thygesen Gjesse, 2010/04/26 14:08:15]

Why not use push (from arm-assembler) for this?

+      str(src2, MemOperand(sp, 4, NegPreIndex), cond);
+    }
+  }
+
+  // Push three registers.  Pushes leftmost register first (to highest address).
+  void Push(Register src1, Register src2, Register src3, Condition cond = al) {
+    ASSERT(!src1.is(src2));
+    ASSERT(!src2.is(src3));
+    ASSERT(!src1.is(src3));
+    if (src1.code() > src2.code()) {
+      if (src2.code() > src3.code()) {
+        stm(db_w, sp, src1.bit() | src2.bit() | src3.bit(), cond);
+      } else {
+        stm(db_w, sp, src1.bit() | src2.bit(), cond);
+        str(src3, MemOperand(sp, 4, NegPreIndex), cond);
+      }
+    } else {
+      str(src1, MemOperand(sp, 4, NegPreIndex), cond);
+      Push(src2, src3, cond);
+    }
+  }
+
+  // Push four registers.  Pushes leftmost register first (to highest address).
+  void Push(Register src1, Register src2,
+            Register src3, Register src4, Condition cond = al) {
+    ASSERT(!src1.is(src2));
+    ASSERT(!src2.is(src3));
+    ASSERT(!src1.is(src3));
+    ASSERT(!src1.is(src4));
+    ASSERT(!src2.is(src4));
+    ASSERT(!src3.is(src4));
+    if (src1.code() > src2.code()) {
+      if (src2.code() > src3.code()) {
+        if (src3.code() > src4.code()) {
+          stm(db_w,
+              sp,
+              src1.bit() | src2.bit() | src3.bit() | src4.bit(),
+              cond);
+        } else {
+          stm(db_w, sp, src1.bit() | src2.bit() | src3.bit(), cond);
+          str(src4, MemOperand(sp, 4, NegPreIndex), cond);
+        }
+      } else {
+        stm(db_w, sp, src1.bit() | src2.bit(), cond);
+        Push(src3, src4, cond);
+      }
+    } else {
+      str(src1, MemOperand(sp, 4, NegPreIndex), cond);
+      Push(src2, src3, src4, cond);
+    }
+  }
+
   // ---------------------------------------------------------------------------
   // Stack limit support