X86: Implement the stupd microop ("store with update", not "stupid") and use it in ENTER.

--HG--
extra : convert_revision : 9151f701162d31ef26298497467c42b7b0ed85d5

src/arch/x86/isa/insts/general_purpose/data_transfer/stack_operations.py

@@ -169,8 +169,7 @@ def macroop ENTER_I_I {
     # t1 is now the masked nesting level, and t2 is the amount of storage.
 
     # Push rbp.
-    st rbp, ss, [1, t0, rsp], "-env.dataSize"
-    subi rsp, rsp, dsz
+    stupd rbp, ss, [1, t0, rsp], "-env.dataSize"
 
     # Save the stack pointer for later
     mov t6, t6, rsp
@@ -186,8 +185,7 @@ def macroop ENTER_I_I {
     limm t4, "ULL(-1)", dataSize=8
 topOfLoop:
     ld t5, ss, [dsz, t4, rbp]
-    st t5, ss, [1, t0, rsp], "-env.dataSize"
-    subi rsp, rsp, dsz
+    stupd t5, ss, [1, t0, rsp], "-env.dataSize"
 
     # If we're not done yet, loop
     subi t4, t4, 1, dataSize=8
@@ -196,8 +194,7 @@ topOfLoop:
 
 bottomOfLoop:
     # Push the old rbp onto the stack
-    st t6, ss, [1, t0, rsp], "-env.dataSize"
-    subi rsp, rsp, dsz
+    stupd t6, ss, [1, t0, rsp], "-env.dataSize"
 
 skipLoop:
     sub rsp, rsp, t2

src/arch/x86/isa/microops/ldstop.isa

@@ -422,6 +422,11 @@ let {{
 
     defineMicroStoreOp('St', 'Mem = Data;')
     defineMicroStoreOp('Stfp', 'Mem = FpData.uqw;')
+    defineMicroStoreOp('Stupd', '''
+            Mem = Data;
+            Base = merge(Base, EA - SegBase, addressSize);
+            ''');
+
 
     iop = InstObjParams("lea", "Lea", 'X86ISA::LdStOp',
             {"code": "Data = merge(Data, EA, dataSize);",