X86: Implement the LOOP instructions.

--HG--
extra : convert_revision : 3ccd0565c83b6d9c9b63f9f7ac2b67839a2c714f

src/arch/x86/isa/decoder/one_byte_opcodes.isa

@@ -472,9 +472,9 @@
         }
         ##include "x87.isa"
         0x1C: decode OPCODE_OP_BOTTOM3 {
-            0x0: loopne_Jb();
-            0x1: loope_Jb();
-            0x2: loop_Jb();
+            0x0: Inst::LOOPNE(Jb);
+            0x1: Inst::LOOPE(Jb);
+            0x2: Inst::LOOP(Jb);
             0x3: Inst::JRCX(Jb);
             0x4: in_Al_Ib();
             0x5: in_eAX_Ib();

src/arch/x86/isa/insts/general_purpose/control_transfer/loop.py

@@ -53,8 +53,22 @@
 #
 # Authors: Gabe Black
 
-microcode = ""
-#let {{
-#    class LOOPcc(Inst):
-#	"GenFault ${new UnimpInstFault}"
-#}};
+microcode = '''
+def macroop LOOP_I {
+    rdip t1
+    subi rcx, rcx, 1, flags=(EZF,), dataSize=asz
+    wripi t1, imm, flags=(nCEZF,)
+};
+
+def macroop LOOPNE_I {
+    rdip t1
+    subi rcx, rcx, 1, flags=(EZF,), dataSize=asz
+    wripi t1, imm, flags=(CSTRnZnEZF,)
+};
+
+def macroop LOOPE_I {
+    rdip t1
+    subi rcx, rcx, 1, flags=(EZF,), dataSize=asz
+    wripi t1, imm, flags=(CSTRZnEZF,)
+};
+'''