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/Decoders/OpCodeT16IfThen.cs | 34 +++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 ARMeilleure/Decoders/OpCodeT16IfThen.cs

(limited to 'ARMeilleure/Decoders/OpCodeT16IfThen.cs')

diff --git a/ARMeilleure/Decoders/OpCodeT16IfThen.cs b/ARMeilleure/Decoders/OpCodeT16IfThen.cs
new file mode 100644
index 00000000..bf84d1d3
--- /dev/null
+++ b/ARMeilleure/Decoders/OpCodeT16IfThen.cs
@@ -0,0 +1,34 @@
+using System.Collections.Generic;
+using System.Reflection.Emit;
+
+namespace ARMeilleure.Decoders
+{
+    class OpCodeT16IfThen : OpCodeT16
+    {
+        public Condition[] IfThenBlockConds { get; }
+
+        public int IfThenBlockSize { get { return IfThenBlockConds.Length; } }
+
+        public new static OpCode Create(InstDescriptor inst, ulong address, int opCode) => new OpCodeT16IfThen(inst, address, opCode);
+
+        public OpCodeT16IfThen(InstDescriptor inst, ulong address, int opCode) : base(inst, address, opCode)
+        {
+            List<Condition> conds = new();
+
+            int cond = (opCode >> 4) & 0xf;
+            int mask = opCode & 0xf;
+
+            conds.Add((Condition)cond);
+
+            while ((mask & 7) != 0)
+            {
+                int newLsb = (mask >> 3) & 1;
+                cond = (cond & 0xe) | newLsb;
+                mask <<= 1;
+                conds.Add((Condition)cond);
+            }
+
+            IfThenBlockConds = conds.ToArray();
+        }
+    }
+}
-- 
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