Changeset 59038 in webkit for trunk/JavaScriptCore/assembler

Timestamp:

May 8, 2010, 1:03:31 PM (15 years ago)

Author:

[email protected]

Message:

2010-05-08 Gabor Loki <​[email protected]>

Reviewed by Gavin Barraclough.

Fix halfword loads on ARM
​https://bugs.webkit.org/show_bug.cgi?id=38741

The BaseIndex and ImplicitAddress are contain 32bit wide offset, but
the load16 functions were working with 8 bit data (encoded in the
instruction). If the offset cannot be encoded in an instruction, it
should be stored in a temporary register.

• assembler/ARMAssembler.h: (JSC::ARMAssembler::getOffsetForHalfwordDataTransfer):
• assembler/MacroAssemblerARM.h: (JSC::MacroAssemblerARM::load16):

Location:

trunk/JavaScriptCore/assembler

Files:

• ARMAssembler.h (modified) (1 diff)
• MacroAssemblerARM.h (modified) (2 diffs)

trunk/JavaScriptCore/assembler/ARMAssembler.h

@@ -826 +826 @@
         ARMWord encodeComplexImm(ARMWord imm, int dest);
 
+        ARMWord getOffsetForHalfwordDataTransfer(ARMWord imm, int tmpReg)
+        {
+            // Encode immediate data in the instruction if it is possible
+            if (imm <= 0xff)
+                return getOp2Byte(imm);
+            // Otherwise, store the data in a temporary register
+            return encodeComplexImm(imm, tmpReg);
+        }
+
         // Memory load/store helpers
 

trunk/JavaScriptCore/assembler/MacroAssemblerARM.h

@@ -268 +268 @@
     void load16(BaseIndex address, RegisterID dest)
     {
-        m_assembler.add_r(ARMRegisters::S0, address.base, m_assembler.lsl(address.index, address.scale));
-        if (address.offset>=0)
-            m_assembler.ldrh_u(dest, ARMRegisters::S0, ARMAssembler::getOp2Byte(address.offset));
-        else
-            m_assembler.ldrh_d(dest, ARMRegisters::S0, ARMAssembler::getOp2Byte(-address.offset));
+        m_assembler.add_r(ARMRegisters::S1, address.base, m_assembler.lsl(address.index, address.scale));
+        load16(Address(ARMRegisters::S1, address.offset), dest);
     }
     
@@ -278 +275 @@
     {
         if (address.offset >= 0)
-            m_assembler.ldrh_u(dest, address.base, ARMAssembler::getOp2Byte(address.offset));
+            m_assembler.ldrh_u(dest, address.base, m_assembler.getOffsetForHalfwordDataTransfer(address.offset, ARMRegisters::S0));
         else
-            m_assembler.ldrh_d(dest, address.base, ARMAssembler::getOp2Byte(-address.offset));   
+            m_assembler.ldrh_d(dest, address.base, m_assembler.getOffsetForHalfwordDataTransfer(-address.offset, ARMRegisters::S0));
     }