From 487a2eaf230d23ebe95cea0ee243a6bb0add5393 Mon Sep 17 00:00:00 2001
From: Dhruv Maroo <dhruvmaru007@gmail.com>
Date: Sun, 17 Sep 2023 00:14:39 +0530
Subject: [PATCH] Add IL implementation for `FABS`

    * Also add `x86_il_{get,set}_st_reg` helper functions
---
 librz/analysis/arch/x86/common.c      | 20 ++++++++++++++++++++
 librz/analysis/arch/x86/common.h      |  3 +++
 librz/analysis/arch/x86/il_fp_ops.inc | 14 ++++++++++++++
 librz/analysis/arch/x86/x86_il.c      |  6 +++++-
 4 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/librz/analysis/arch/x86/common.c b/librz/analysis/arch/x86/common.c
index b4e605e6839..884f272a6ea 100644
--- a/librz/analysis/arch/x86/common.c
+++ b/librz/analysis/arch/x86/common.c
@@ -1077,4 +1077,24 @@ RzILOpEffect *x86_il_set_flags(RZ_OWN RzILOpPure *val, unsigned int size) {
 	return SEQ2(set_val, eff);
 }
 
+static bool check_st_reg(X86Reg reg) {
+	return reg >= X86_REG_ST0 && reg <= X86_REG_ST7;
+}
+
+RzILOpFloat *x86_il_get_st_reg(X86Reg reg) {
+	if (check_st_reg(reg)) {
+		return BV2F(RZ_FLOAT_IEEE754_BIN_64, VARG(x86_registers[reg]));
+	}
+
+	return NULL;
+}
+
+RzILOpEffect *x86_il_set_st_reg(X86Reg reg, RzILOpFloat *val) {
+	if (check_st_reg(reg)) {
+		return SETG(x86_registers[reg], F2BV(val));
+	}
+
+	return NULL;
+}
+
 #include <rz_il/rz_il_opbuilder_end.h>
diff --git a/librz/analysis/arch/x86/common.h b/librz/analysis/arch/x86/common.h
index afede0a847b..6b4cba2af7f 100644
--- a/librz/analysis/arch/x86/common.h
+++ b/librz/analysis/arch/x86/common.h
@@ -104,4 +104,7 @@ RzILOpEffect *x86_il_set_arithmetic_flags_except_cf_bits(RZ_OWN RzILOpPure *res,
 RzILOpPure *x86_il_get_flags(unsigned int size);
 RzILOpEffect *x86_il_set_flags(RZ_OWN RzILOpPure *val, unsigned int size);
 
+RzILOpFloat *x86_il_get_st_reg(X86Reg reg);
+RzILOpEffect *x86_il_set_st_reg(X86Reg reg, RzILOpFloat *val);
+
 #endif // X86_IL_COMMON_H
diff --git a/librz/analysis/arch/x86/il_fp_ops.inc b/librz/analysis/arch/x86/il_fp_ops.inc
index 4445e4cb2f4..0c27d4f8bf0 100644
--- a/librz/analysis/arch/x86/il_fp_ops.inc
+++ b/librz/analysis/arch/x86/il_fp_ops.inc
@@ -11,3 +11,17 @@
  *  - https://eng.libretexts.org/Bookshelves/Computer_Science/Programming_Languages/x86-64_Assembly_Language_Programming_with_Ubuntu_(Jorgensen)/18%3A_Floating-Point_Instructions
  *  - https://en.wikibooks.org/wiki/X86_Assembly/Floating_Point#Floating-Point_Instruction_Set
  */
+
+#include "common.h"
+#include <rz_il/rz_il_opbuilder_begin.h>
+
+/* Arithmetic instructions */
+
+/**
+ * FABS
+ * Clears the sign bit of st(0) to create absolute value
+ */
+IL_LIFTER(fabs) {
+	RzILOpFloat *abs_value = FABS(x86_il_get_st_reg(X86_REG_ST0));
+	return x86_il_set_st_reg(X86_REG_ST0, abs_value);
+}
diff --git a/librz/analysis/arch/x86/x86_il.c b/librz/analysis/arch/x86/x86_il.c
index a4aa12fc619..be309653a21 100644
--- a/librz/analysis/arch/x86/x86_il.c
+++ b/librz/analysis/arch/x86/x86_il.c
@@ -3,6 +3,7 @@
 
 #include "x86_il.h"
 #include "il_ops.inc"
+#include "il_fp_ops.inc"
 
 #define COMMON_REGS \
 	"cs", /* X86_REG_CS */ \
@@ -240,7 +241,10 @@ x86_il_ins x86_ins[X86_INS_ENDING] = {
 	[X86_INS_INSW] = x86_il_unimpl,
 	[X86_INS_OUTSB] = x86_il_unimpl,
 	[X86_INS_OUTSW] = x86_il_unimpl,
-	[X86_INS_LEAVE] = x86_il_leave
+	[X86_INS_LEAVE] = x86_il_leave,
+
+	/* floating-point instructions */
+	[X86_INS_FABS] = x86_il_fabs
 };
 
 void label_int(RzILVM *vm, RzILOpEffect *op);