x86: implement x87 fp instruction fnstsw

This patch implements the fnstsw instruction. The code was originally written
by Vince Weaver. Gabe had made some comments about the code, but those were
never addressed. This patch addresses those comments.

2 files changed, 28 insertions, 2 deletions

diff --git a/src/arch/x86/isa/insts/x87/control/save_and_restore_x87_control_word.py b/src/arch/x86/isa/insts/x87/control/save_and_restore_x87_control_word.py
index 0fc4ef7b7..5657c8d47 100644
--- a/src/arch/x86/isa/insts/x87/control/save_and_restore_x87_control_word.py
+++ b/src/arch/x86/isa/insts/x87/control/save_and_restore_x87_control_word.py
@@ -38,5 +38,15 @@
 microcode = '''
 # FLDCW
 # FSTCW
-# FNSTCW
+
+def macroop FNSTCW_M {
+    rdval t1, fcw
+    st t1, seg, sib, disp, dataSize=2
+};
+
+def macroop FNSTCW_P {
+    rdip t7
+    rdval t1, fcw
+    st t1, seg, sib, disp, dataSize=2
+};
 '''
diff --git a/src/arch/x86/isa/insts/x87/control/save_x87_status_word.py b/src/arch/x86/isa/insts/x87/control/save_x87_status_word.py
index 2739852a4..65ff8006b 100644
--- a/src/arch/x86/isa/insts/x87/control/save_x87_status_word.py
+++ b/src/arch/x86/isa/insts/x87/control/save_x87_status_word.py
@@ -36,6 +36,22 @@
 # Authors: Gabe Black
 
 microcode = '''
+
 # FSTSW
-# FNSTSW
+
+def macroop FNSTSW_R {
+    rdval t1, fsw
+    mov rax, rax, t1, dataSize=2
+};
+
+def macroop FNSTSW_M {
+    rdval t1, fsw
+    st t1, seg, sib, disp, dataSize=2
+};
+
+def macroop FNSTSW_P {
+    rdip t7
+    rdval t1, fsw
+    st t1, seg, riprel, disp, dataSize=2
+};
 '''