From 98e05ee4b7aa8a08088b1f0cd6c581bb50f11395 Mon Sep 17 00:00:00 2001
From: merry <git@mary.rs>
Date: Thu, 17 Feb 2022 22:39:45 +0000
Subject: ARMeilleure: Thumb support (All T16 instructions) (#3105)

* Decoders: Add InITBlock argument

* OpCodeTable: Minor cleanup

* OpCodeTable: Remove existing thumb instruction implementations

* OpCodeTable: Prepare for thumb instructions

* OpCodeTables: Improve thumb fast lookup

* Tests: Prepare for thumb tests

* T16: Implement BX

* T16: Implement LSL/LSR/ASR (imm)

* T16: Implement ADDS, SUBS (reg)

* T16: Implement ADDS, SUBS (3-bit immediate)

* T16: Implement MOVS, CMP, ADDS, SUBS (8-bit immediate)

* T16: Implement ANDS, EORS, LSLS, LSRS, ASRS, ADCS, SBCS, RORS, TST, NEGS, CMP, CMN, ORRS, MULS, BICS, MVNS (low registers)

* T16: Implement ADD, CMP, MOV (high reg)

* T16: Implement BLX (reg)

* T16: Implement LDR (literal)

* T16: Implement {LDR,STR}{,H,B,SB,SH} (register)

* T16: Implement {LDR,STR}{,B,H} (immediate)

* T16: Implement LDR/STR (SP)

* T16: Implement ADR

* T16: Implement Add to SP (immediate)

* T16: Implement ADD/SUB (SP)

* T16: Implement SXTH, SXTB, UXTH, UTXB

* T16: Implement CBZ, CBNZ

* T16: Implement PUSH, POP

* T16: Implement REV, REV16, REVSH

* T16: Implement NOP

* T16: Implement LDM, STM

* T16: Implement SVC

* T16: Implement B (conditional)

* T16: Implement B (unconditional)

* T16: Implement IT

* fixup! T16: Implement ADD/SUB (SP)

* fixup! T16: Implement Add to SP (immediate)

* fixup! T16: Implement IT

* CpuTestThumb: Add randomized tests

* Remove inITBlock argument

* Address nits

* Use index to handle IfThenBlockState

* Reduce line noise

* fixup

* nit
---
 ARMeilleure/Instructions/InstEmitAluHelper.cs | 30 ++++++++++++++++++---------
 1 file changed, 20 insertions(+), 10 deletions(-)

(limited to 'ARMeilleure/Instructions/InstEmitAluHelper.cs')

diff --git a/ARMeilleure/Instructions/InstEmitAluHelper.cs b/ARMeilleure/Instructions/InstEmitAluHelper.cs
index 32440283..fe555767 100644
--- a/ARMeilleure/Instructions/InstEmitAluHelper.cs
+++ b/ARMeilleure/Instructions/InstEmitAluHelper.cs
@@ -12,6 +12,18 @@ namespace ARMeilleure.Instructions
 {
     static class InstEmitAluHelper
     {
+        public static bool ShouldSetFlags(ArmEmitterContext context)
+        {
+            IOpCode32Alu op = (IOpCode32Alu)context.CurrOp;
+
+            if (op.SetFlags == null)
+            {
+                return !context.IsInIfThenBlock;
+            }
+
+            return op.SetFlags.Value;
+        }
+
         public static void EmitNZFlagsCheck(ArmEmitterContext context, Operand d)
         {
             SetFlag(context, PState.NFlag, context.ICompareLess (d, Const(d.Type, 0)));
@@ -183,9 +195,9 @@ namespace ARMeilleure.Instructions
             switch (context.CurrOp)
             {
                 // ARM32.
-                case OpCode32AluImm op:
+                case IOpCode32AluImm op:
                 {
-                    if (op.SetFlags && op.IsRotated)
+                    if (ShouldSetFlags(context) && op.IsRotated)
                     {
                         SetFlag(context, PState.CFlag, Const((uint)op.Immediate >> 31));
                     }
@@ -195,10 +207,8 @@ namespace ARMeilleure.Instructions
 
                 case OpCode32AluImm16 op: return Const(op.Immediate);
 
-                case OpCode32AluRsImm op: return GetMShiftedByImmediate(context, op, setCarry);
-                case OpCode32AluRsReg op: return GetMShiftedByReg(context, op, setCarry);
-
-                case OpCodeT16AluImm8 op: return Const(op.Immediate);
+                case IOpCode32AluRsImm op: return GetMShiftedByImmediate(context, op, setCarry);
+                case IOpCode32AluRsReg op: return GetMShiftedByReg(context, op, setCarry);
 
                 case IOpCode32AluReg op: return GetIntA32(context, op.Rm);
 
@@ -249,7 +259,7 @@ namespace ARMeilleure.Instructions
         }
 
         // ARM32 helpers.
-        public static Operand GetMShiftedByImmediate(ArmEmitterContext context, OpCode32AluRsImm op, bool setCarry)
+        public static Operand GetMShiftedByImmediate(ArmEmitterContext context, IOpCode32AluRsImm op, bool setCarry)
         {
             Operand m = GetIntA32(context, op.Rm);
 
@@ -267,7 +277,7 @@ namespace ARMeilleure.Instructions
 
             if (shift != 0)
             {
-                setCarry &= op.SetFlags;
+                setCarry &= ShouldSetFlags(context);
 
                 switch (op.ShiftType)
                 {
@@ -305,7 +315,7 @@ namespace ARMeilleure.Instructions
             return shift;
         }
 
-        public static Operand GetMShiftedByReg(ArmEmitterContext context, OpCode32AluRsReg op, bool setCarry)
+        public static Operand GetMShiftedByReg(ArmEmitterContext context, IOpCode32AluRsReg op, bool setCarry)
         {
             Operand m = GetIntA32(context, op.Rm);
             Operand s = context.ZeroExtend8(OperandType.I32, GetIntA32(context, op.Rs));
@@ -314,7 +324,7 @@ namespace ARMeilleure.Instructions
             Operand zeroResult = m;
             Operand shiftResult = m;
 
-            setCarry &= op.SetFlags;
+            setCarry &= ShouldSetFlags(context);
 
             switch (op.ShiftType)
             {
-- 
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