From 1b5fcfd8d178789759644e3f2b4fb48fb0d2455f Mon Sep 17 00:00:00 2001
From: Lioncash <mathew1800@gmail.com>
Date: Wed, 10 Feb 2021 16:11:09 -0500
Subject: [PATCH] thumb32: Implement SXTB16
---
src/frontend/A32/decoder/thumb32.inc | 2 +-
.../impl/thumb32_data_processing_register.cpp | 14 ++++++++++++++
src/frontend/A32/translate/impl/translate_thumb.h | 1 +
3 files changed, 16 insertions(+), 1 deletion(-)
diff --git a/src/frontend/A32/decoder/thumb32.inc b/src/frontend/A32/decoder/thumb32.inc
index dc0dc136..acee99a4 100644
--- a/src/frontend/A32/decoder/thumb32.inc
+++ b/src/frontend/A32/decoder/thumb32.inc
@@ -199,7 +199,7 @@ INST(thumb32_SXTH, "SXTH", "11111010000011111111dd
INST(thumb32_SXTAH, "SXTAH", "111110100000nnnn1111dddd10rrmmmm")
INST(thumb32_UXTH, "UXTH", "11111010000111111111dddd10rrmmmm")
INST(thumb32_UXTAH, "UXTAH", "111110100001nnnn1111dddd10rrmmmm")
-//INST(thumb32_SXTB16, "SXTB16", "11111010001011111111----1-------")
+INST(thumb32_SXTB16, "SXTB16", "11111010001011111111dddd10rrmmmm")
//INST(thumb32_SXTAB16, "SXTAB16", "111110100010----1111----1-------")
//INST(thumb32_UXTB16, "UXTB16", "11111010001111111111----1-------")
//INST(thumb32_UXTAB16, "UXTAB16", "111110100011----1111----1-------")
diff --git a/src/frontend/A32/translate/impl/thumb32_data_processing_register.cpp b/src/frontend/A32/translate/impl/thumb32_data_processing_register.cpp
index 2ca195c7..0c5715fe 100644
--- a/src/frontend/A32/translate/impl/thumb32_data_processing_register.cpp
+++ b/src/frontend/A32/translate/impl/thumb32_data_processing_register.cpp
@@ -11,6 +11,20 @@ static IR::U32 Rotate(A32::IREmitter& ir, Reg m, SignExtendRotation rotate) {
return ir.RotateRight(ir.GetRegister(m), ir.Imm8(rotate_by), ir.Imm1(0)).result;
}
+bool ThumbTranslatorVisitor::thumb32_SXTB16(Reg d, SignExtendRotation rotate, Reg m) {
+ if (d == Reg::PC || m == Reg::PC) {
+ return UnpredictableInstruction();
+ }
+
+ const auto rotated = Rotate(ir, m, rotate);
+ const auto low_byte = ir.And(rotated, ir.Imm32(0x00FF00FF));
+ const auto sign_bit = ir.And(rotated, ir.Imm32(0x00800080));
+ const auto result = ir.Or(low_byte, ir.Mul(sign_bit, ir.Imm32(0x1FE)));
+
+ ir.SetRegister(d, result);
+ return true;
+}
+
bool ThumbTranslatorVisitor::thumb32_SXTH(Reg d, SignExtendRotation rotate, Reg m) {
if (d == Reg::PC || m == Reg::PC) {
return UnpredictableInstruction();
diff --git a/src/frontend/A32/translate/impl/translate_thumb.h b/src/frontend/A32/translate/impl/translate_thumb.h
index 33792a82..af2bf46d 100644
--- a/src/frontend/A32/translate/impl/translate_thumb.h
+++ b/src/frontend/A32/translate/impl/translate_thumb.h
@@ -122,6 +122,7 @@ struct ThumbTranslatorVisitor final {
bool thumb32_UDF();
// thumb32 data processing (register) instructions
+ bool thumb32_SXTB16(Reg d, SignExtendRotation rotate, Reg m);
bool thumb32_SXTH(Reg d, SignExtendRotation rotate, Reg m);
bool thumb32_SXTAH(Reg n, Reg d, SignExtendRotation rotate, Reg m);
bool thumb32_UXTH(Reg d, SignExtendRotation rotate, Reg m);