Add semantics for several more iadd with carry; Add xform_correct() and doc cleanup

lib/cretonne/meta/base/semantics.py

@@ -1,7 +1,8 @@
 from __future__ import absolute_import
 from semantics.primitives import prim_to_bv, prim_from_bv, bvsplit, bvconcat,\
     bvadd, bvult, bvzeroext
-from .instructions import vsplit, vconcat, iadd, iadd_cout, icmp, bextend
+from .instructions import vsplit, vconcat, iadd, iadd_cout, icmp, bextend, \
+    isplit, iconcat, iadd_cin, iadd_carry
 from .immediates import intcc
 from cdsl.xform import Rtl
 from cdsl.ast import Var
@@ -13,18 +14,24 @@ y = Var('y')
 a = Var('a')
 b = Var('b')
 c_out = Var('c_out')
+c_in = Var('c_in')
 bvc_out = Var('bvc_out')
+bvc_in = Var('bvc_in')
 xhi = Var('xhi')
 yhi = Var('yhi')
 ahi = Var('ahi')
+bhi = Var('bhi')
 xlo = Var('xlo')
 ylo = Var('ylo')
 alo = Var('alo')
+blo = Var('blo')
 lo = Var('lo')
 hi = Var('hi')
 bvx = Var('bvx')
 bvy = Var('bvy')
 bva = Var('bva')
+bvt = Var('bvt')
+bvs = Var('bvs')
 bva_wide = Var('bva_wide')
 bvlo = Var('bvlo')
 bvhi = Var('bvhi')
@@ -51,16 +58,34 @@ vconcat.set_semantics(
 
 iadd.set_semantics(
     a << iadd(x, y),
-    (Rtl(bvx << prim_to_bv(x),
-         bvy << prim_to_bv(y),
-         bva << bvadd(bvx, bvy),
-         a << prim_from_bv(bva)),
-     [InTypeset(x.get_typevar(), ScalarTS)]),
-    Rtl((xlo, xhi) << vsplit(x),
+    (Rtl(
+        bvx << prim_to_bv(x),
+        bvy << prim_to_bv(y),
+        bva << bvadd(bvx, bvy),
+        a << prim_from_bv(bva)
+    ), [InTypeset(x.get_typevar(), ScalarTS)]),
+    Rtl(
+        (xlo, xhi) << vsplit(x),
         (ylo, yhi) << vsplit(y),
         alo << iadd(xlo, ylo),
         ahi << iadd(xhi, yhi),
-        a << vconcat(alo, ahi)))
+        a << vconcat(alo, ahi)
+    ))
+
+#
+# Integer arithmetic with carry and/or borrow.
+#
+iadd_cin.set_semantics(
+    a << iadd_cin(x, y, c_in),
+    Rtl(
+        bvx << prim_to_bv(x),
+        bvy << prim_to_bv(y),
+        bvc_in << prim_to_bv(c_in),
+        bvs << bvzeroext(bvc_in),
+        bvt << bvadd(bvx, bvy),
+        bva << bvadd(bvt, bvs),
+        a << prim_from_bv(bva)
+    ))
 
 iadd_cout.set_semantics(
     (a, c_out) << iadd_cout(x, y),
@@ -73,6 +98,20 @@ iadd_cout.set_semantics(
         c_out << prim_from_bv(bvc_out)
     ))
 
+iadd_carry.set_semantics(
+    (a, c_out) << iadd_carry(x, y, c_in),
+    Rtl(
+        bvx << prim_to_bv(x),
+        bvy << prim_to_bv(y),
+        bvc_in << prim_to_bv(c_in),
+        bvs << bvzeroext(bvc_in),
+        bvt << bvadd(bvx, bvy),
+        bva << bvadd(bvt, bvs),
+        bvc_out << bvult(bva, bvx),
+        a << prim_from_bv(bva),
+        c_out << prim_from_bv(bvc_out)
+    ))
+
 bextend.set_semantics(
     a << bextend(x),
     (Rtl(
@@ -80,10 +119,12 @@ bextend.set_semantics(
         bvy << bvzeroext(bvx),
         a << prim_from_bv(bvy)
     ), [InTypeset(x.get_typevar(), ScalarTS)]),
-    Rtl((xlo, xhi) << vsplit(x),
+    Rtl(
+        (xlo, xhi) << vsplit(x),
         alo << bextend(xlo),
         ahi << bextend(xhi),
-        a << vconcat(alo, ahi)))
+        a << vconcat(alo, ahi)
+    ))
 
 icmp.set_semantics(
     a << icmp(intcc.ult, x, y),
@@ -94,9 +135,47 @@ icmp.set_semantics(
         bva_wide << bvzeroext(bva),
         a << prim_from_bv(bva_wide),
     ), [InTypeset(x.get_typevar(), ScalarTS)]),
-    Rtl((xlo, xhi) << vsplit(x),
+    Rtl(
+        (xlo, xhi) << vsplit(x),
         (ylo, yhi) << vsplit(y),
         alo << icmp(intcc.ult, xlo, ylo),
         ahi << icmp(intcc.ult, xhi, yhi),
         b << vconcat(alo, ahi),
-        a << bextend(b)))
+        a << bextend(b)
+    ))
+
+#
+# Legalization helper instructions.
+#
+
+isplit.set_semantics(
+    (xlo, xhi) << isplit(x),
+    (Rtl(
+        bvx << prim_to_bv(x),
+        (bvlo, bvhi) << bvsplit(bvx),
+        xlo << prim_from_bv(bvlo),
+        xhi << prim_from_bv(bvhi)
+    ), [InTypeset(x.get_typevar(), ScalarTS)]),
+    Rtl(
+        (a, b) << vsplit(x),
+        (alo, ahi) << isplit(a),
+        (blo, bhi) << isplit(b),
+        xlo << vconcat(alo, blo),
+        xhi << vconcat(bhi, bhi)
+    ))
+
+iconcat.set_semantics(
+    x << iconcat(xlo, xhi),
+    (Rtl(
+        bvlo << prim_to_bv(xlo),
+        bvhi << prim_to_bv(xhi),
+        bvx << bvconcat(bvlo, bvhi),
+        x << prim_from_bv(bvx)
+    ), [InTypeset(x.get_typevar(), ScalarTS)]),
+    Rtl(
+        (alo, ahi) << vsplit(xlo),
+        (blo, bhi) << vsplit(xhi),
+        a << iconcat(alo, blo),
+        b << iconcat(ahi, bhi),
+        x << vconcat(a, b),
+    ))