From dce4de037ddd1a59bd7d42ab30a662b142e2deba Mon Sep 17 00:00:00 2001
From: Florian Bernd <git@flobernd.de>
Date: Thu, 31 Oct 2024 13:29:48 +0100
Subject: [PATCH] Add `uses_egpr` APX info

---
 include/Zydis/DecoderTypes.h |  4 ++++
 src/Decoder.c                | 17 +++++++++++++++--
 tools/ZydisInfo.c            |  5 +++--
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/include/Zydis/DecoderTypes.h b/include/Zydis/DecoderTypes.h
index 3c7a3312..f4179872 100644
--- a/include/Zydis/DecoderTypes.h
+++ b/include/Zydis/DecoderTypes.h
@@ -1215,6 +1215,10 @@ typedef struct ZydisDecodedInstructionAvx_
  */
 typedef struct ZydisDecodedInstructionApx_
 {
+    /**
+     * Signals, if the instruction uses the extended GRP registers (R16..R31).
+     */
+    ZyanBool uses_egpr;
     /**
      * Signals, if the APX `no flags` functionality enabled for the instruction.
      */
diff --git a/src/Decoder.c b/src/Decoder.c
index 5098016f..621e2eaf 100644
--- a/src/Decoder.c
+++ b/src/Decoder.c
@@ -4450,7 +4450,7 @@ static ZyanStatus ZydisNodeHandlerMvexE(const ZydisDecodedInstruction* instructi
  * - `def_vvvv` -> `ZydisRegisterKind`
  */
 static ZyanStatus ZydisPopulateRegisterIds(ZydisDecoderContext* context,
-    const ZydisDecodedInstruction* instruction, ZyanU8 def_reg, ZyanU8 def_rm, ZyanU8 def_vvvv)
+    ZydisDecodedInstruction* instruction, ZyanU8 def_reg, ZyanU8 def_rm, ZyanU8 def_vvvv)
 {
     ZYAN_ASSERT(context);
     ZYAN_ASSERT(instruction);
@@ -4673,6 +4673,19 @@ static ZyanStatus ZydisPopulateRegisterIds(ZydisDecoderContext* context,
     context->reg_info.id_base   = !is_mod_reg          ? id_base   : -1;
     context->reg_info.id_index  = !is_mod_reg          ? id_index  : -1;
 
+    // Update APX info
+
+    const ZyanBool has_egpr_reg   = (def_reg == ZYDIS_REGKIND_GPR) && (id_reg >= 16);
+    const ZyanBool has_egpr_rm    = is_mod_reg && (def_rm == ZYDIS_REGKIND_GPR) && (id_rm >= 16);
+    const ZyanBool has_egpr_vvvv  = (def_vvvv == ZYDIS_REGKIND_GPR) && (id_vvvv >= 16);
+    const ZyanBool has_egpr_base  = !is_mod_reg && (id_base >= 16);
+    const ZyanBool has_egpr_index = !is_mod_reg && !has_vsib && (id_index >= 16);
+
+    if (has_egpr_reg || has_egpr_rm || has_egpr_vvvv || has_egpr_base || has_egpr_index)
+    {
+        instruction->apx.uses_egpr = ZYAN_TRUE;
+    }
+
     return ZYAN_STATUS_SUCCESS;
 }
 
@@ -4688,7 +4701,7 @@ static ZyanStatus ZydisPopulateRegisterIds(ZydisDecoderContext* context,
  * This function is called immediately after a valid instruction-definition was found.
  */
 static ZyanStatus ZydisCheckErrorConditions(ZydisDecoderState* state,
-    const ZydisDecodedInstruction* instruction, const ZydisInstructionDefinition* definition)
+    ZydisDecodedInstruction* instruction, const ZydisInstructionDefinition* definition)
 {
     ZYAN_ASSERT(state);
     ZYAN_ASSERT(instruction);
diff --git a/tools/ZydisInfo.c b/tools/ZydisInfo.c
index 8a81e6ab..ad265819 100644
--- a/tools/ZydisInfo.c
+++ b/tools/ZydisInfo.c
@@ -863,8 +863,9 @@ static void PrintAPXInfo(const ZydisDecodedInstruction* instruction)
 
     PrintSectionHeader("APX");
 
-    PRINT_VALUE_B("NF", "%s", instruction->apx.has_nf ? "Y" : "N");
-    PRINT_VALUE_B("ZU", "%s", instruction->apx.has_zu ? "Y" : "N");
+    PRINT_VALUE_B("USES_EGPR", "%s", instruction->apx.uses_egpr ? "Y" : "N");
+    PRINT_VALUE_B("HAS_NF", "%s", instruction->apx.has_nf ? "Y" : "N");
+    PRINT_VALUE_B("HAS_ZU", "%s", instruction->apx.has_zu ? "Y" : "N");
     PRINT_VALUE_B("SCC", "%s", strings_scc[instruction->apx.scc]);
 }