ARM: add fstmx and fldmx instructions for assembly

These instructions are deprecated oddities, but we still need to be able to
disassemble (and reassemble) them if and when they're encountered.

Patch by Amaury de la Vieuville.

llvm-svn: 183011

1 files changed, 15 insertions, 2 deletions

diff --git a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 9c13c604638..824ffbf3386 100644
--- a/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/llvm/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -1150,6 +1150,13 @@ static DecodeStatus DecodeSPRRegListOperand(MCInst &Inst, unsigned Val,
   unsigned Vd = fieldFromInstruction(Val, 8, 5);
   unsigned regs = fieldFromInstruction(Val, 0, 8);
 
+  // In case of unpredictable encoding, tweak the operands.
+  if (regs == 0 || (Vd + regs) > 32) {
+    regs = Vd + regs > 32 ? 32 - Vd : regs;
+    regs = std::max( 1u, regs);
+    S = MCDisassembler::SoftFail;
+  }
+
   if (!Check(S, DecodeSPRRegisterClass(Inst, Vd, Address, Decoder)))
     return MCDisassembler::Fail;
   for (unsigned i = 0; i < (regs - 1); ++i) {
@@ -1165,9 +1172,15 @@ static DecodeStatus DecodeDPRRegListOperand(MCInst &Inst, unsigned Val,
   DecodeStatus S = MCDisassembler::Success;
 
   unsigned Vd = fieldFromInstruction(Val, 8, 5);
-  unsigned regs = fieldFromInstruction(Val, 0, 8);
+  unsigned regs = fieldFromInstruction(Val, 1, 7);
 
-  regs = regs >> 1;
+  // In case of unpredictable encoding, tweak the operands.
+  if (regs == 0 || regs > 16 || (Vd + regs) > 32) {
+    regs = Vd + regs > 32 ? 32 - Vd : regs;
+    regs = std::max( 1u, regs);
+    regs = std::min(16u, regs);
+    S = MCDisassembler::SoftFail;
+  }
 
   if (!Check(S, DecodeDPRRegisterClass(Inst, Vd, Address, Decoder)))
       return MCDisassembler::Fail;