[llvm] r175707 - Mips specific standalone assembler addressing mode %hi and %lo.

[Jack Carter]

Author: jacksprat
Date: Wed Feb 20 20:09:31 2013
New Revision: 175707

URL: http://llvm.org/viewvc/llvm-project?rev=175707&view=rev
Log:
Mips specific standalone assembler addressing mode %hi and %lo.

The constructs %hi() and %lo() represent the high and low 16 
bits of the address. 
Because the 16 bit offset field of an LW instruction is 
interpreted as signed, if bit 15 of the low part is 1 then the 
low part will act as a negative and 1 needs to be added to the 
high part.

Contributer: Vladimir Medic

Added:
    llvm/trunk/test/MC/Mips/hilo-addressing.s
Modified:
    llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
    llvm/trunk/test/MC/Mips/mips_directives.s

Modified: llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp?rev=175707&r1=175706&r2=175707&view=diff
==============================================================================
--- llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp (original)
+++ llvm/trunk/lib/Target/Mips/AsmParser/MipsAsmParser.cpp Wed Feb 20 20:09:31 2013
@@ -888,7 +888,12 @@ bool MipsAsmParser::parseRelocOperand(co
     if (Str == "lo") {
       Val = Val & 0xffff;
     } else if (Str == "hi") {
+      int LoSign = Val & 0x8000;
       Val = (Val & 0xffff0000) >> 16;
+      //lower part is treated as signed int, so if it is negative
+      //we must add 1 to hi part to compensate
+      if (LoSign)
+        Val++;
     }
     Res = MCConstantExpr::Create(Val, getContext());
     return false;

Added: llvm/trunk/test/MC/Mips/hilo-addressing.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Mips/hilo-addressing.s?rev=175707&view=auto
==============================================================================
--- llvm/trunk/test/MC/Mips/hilo-addressing.s (added)
+++ llvm/trunk/test/MC/Mips/hilo-addressing.s Wed Feb 20 20:09:31 2013
@@ -0,0 +1,11 @@
+# RUN: llvm-mc -show-encoding -triple mips-unknown-unknown %s | FileCheck %s
+
+  .ent hilo_test
+     .equ    addr, 0xdeadbeef
+# CHECK: # encoding: [0x3c,0x04,0xde,0xae]
+    lui $4,%hi(addr)
+# CHECK: # encoding: [0x03,0xe0,0x00,0x08]
+    jr  $31
+# CHECK: # encoding: [0x80,0x82,0xbe,0xef]
+    lb  $2,%lo(addr)($4)
+    .end hilo_test

Modified: llvm/trunk/test/MC/Mips/mips_directives.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/Mips/mips_directives.s?rev=175707&r1=175706&r2=175707&view=diff
==============================================================================
--- llvm/trunk/test/MC/Mips/mips_directives.s (original)
+++ llvm/trunk/test/MC/Mips/mips_directives.s Wed Feb 20 20:09:31 2013
@@ -1,5 +1,5 @@
-# RUN: llvm-mc -triple mips-unknown-unknown %s | FileCheck %s
-#this test produces no output so there isS no FileCheck call
+# RUN: llvm-mc -show-encoding -triple mips-unknown-unknown %s | FileCheck %s
+#
 $BB0_2:
   .ent directives_test
     .frame    $sp,0,$ra
@@ -17,4 +17,3 @@ $JTI0_0:
     .set macro
     .set reorder
     .set  at=$a0
-    .end directives_test