Narrow right shifts need to encode their immediates differently from a normal

shift.

   16-bit: imm6<5:3> = '001', 8 - <imm> is encded in imm6<2:0>
   32-bit: imm6<5:4> = '01',16 - <imm> is encded in imm6<3:0>
   64-bit: imm6<5> = '1', 32 - <imm> is encded in imm6<4:0>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126723 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/Target/ARM/ARMInstrFormats.td b/lib/Target/ARM/ARMInstrFormats.td
index 359ac45..cf8c472 100644
--- a/lib/Target/ARM/ARMInstrFormats.td
+++ b/lib/Target/ARM/ARMInstrFormats.td
@@ -221,6 +221,22 @@ def neg_zero : Operand<i32> {
   let PrintMethod = "printNegZeroOperand";
 }
 
+// Narrow Shift Right Immediate - A narrow shift right immediate is encoded
+// differently from other shift immediates. The imm6 field is encoded like so:
+//
+//   16-bit: imm6<5:3> = '001', 8 - <imm> is encded in imm6<2:0>
+//   32-bit: imm6<5:4> = '01',16 - <imm> is encded in imm6<3:0>
+//   64-bit: imm6<5> = '1', 32 - <imm> is encded in imm6<4:0>
+def nsr16_imm : Operand<i32> {
+  let EncoderMethod = "getNarrowShiftRight16Imm";
+}
+def nsr32_imm : Operand<i32> {
+  let EncoderMethod = "getNarrowShiftRight32Imm";
+}
+def nsr64_imm : Operand<i32> {
+  let EncoderMethod = "getNarrowShiftRight64Imm";
+}
+
 //===----------------------------------------------------------------------===//
 // ARM Instruction templates.
 //