[hackers] [scc/qbe] [cc2-qbe] Add cast() || Roberto E. Vargas Caballero

[git]

commit fa9a898e3d16f7f133e563e0cdd36a24724359d9
Author:     Roberto E. Vargas Caballero <k...@shike2.com>
AuthorDate: Tue Aug 16 09:10:13 2016 +0200
Commit:     Roberto E. Vargas Caballero <k...@shike2.com>
CommitDate: Wed Aug 17 14:29:25 2016 +0200

    [cc2-qbe] Add cast()
    
    This code is directly taken and adapted from the old
    cgen for qbe.

diff --git a/cc2/arch/qbe/cgen.c b/cc2/arch/qbe/cgen.c
index 096089e..2e52dc4 100644
--- a/cc2/arch/qbe/cgen.c
+++ b/cc2/arch/qbe/cgen.c
@@ -90,7 +90,7 @@ static char opasmd[] = {
        [OCPL] = ASCPLD
 };
 
-extern Type int32type;
+extern Type int32type, uint32type;
 
 static Node *
 tmpnode(Node *np, Type *tp)
@@ -136,6 +136,80 @@ load(Node *np, Node *new)
        return new;
 }
 
+static Node *rhs(Node *np, Node *new);
+
+static Node *
+cast(Type *td, Node *ns, Node *nd)
+{
+       Type *ts;
+       Node aux1, aux2;
+       int op, d_isint, s_isint;
+
+       ts = &ns->type;
+       d_isint = (td->flags & INTF) != 0;
+       s_isint = (ts->flags & INTF) != 0;
+
+       if (d_isint && s_isint) {
+               if (td->size <= ts->size)
+                       return nd;
+               assert(td->size == 4 || td->size == 8);
+               switch (ts->size) {
+               case 1:
+                       op = (td->size == 4) ? ASEXTBW : ASEXTBL;
+                       break;
+               case 2:
+                       op = (td->size == 4) ? ASEXTHW : ASEXTHL;
+                       break;
+               case 4:
+                       op = ASEXTWL;
+                       break;
+               default:
+                       abort();
+               }
+               /*
+                * unsigned version of operations are always +1 the
+                * signed version
+                */
+               op += (td->flags & SIGNF) == 0;
+       } else if (d_isint) {
+               /* conversion from float to int */
+               switch (ts->size) {
+               case 4:
+                       op = (td->size == 8) ? ASSTOL : ASSTOW;
+                       break;
+               case 8:
+                       op = (td->size == 8) ? ASDTOL : ASDTOW;
+                       break;
+               default:
+                       abort();
+               }
+               /* TODO: Add signess */
+       } else if (s_isint) {
+               /* conversion from int to float */
+               switch (ts->size) {
+               case 1:
+               case 2:
+                       ts = (ts->flags&SIGNF) ? &int32type : &uint32type;
+                       ns = cast(ts, ns, tmpnode(&aux2, ts));
+               case 4:
+                       op = (td->size == 8) ? ASSWTOD : ASSWTOS;
+                       break;
+               case 8:
+                       op = (td->size == 8) ? ASSLTOD : ASSLTOS;
+                       break;
+               default:
+                       abort();
+               }
+               /* TODO: Add signess */
+       } else {
+               /* conversion from float to float */
+               op = (td->size == 4) ? ASEXTS : ASTRUNCD;
+       }
+
+       code(op, tmpnode(nd, td), ns, NULL);
+       return nd;
+}
+
 static Node *
 assign(Node *to, Node *from)
 {
@@ -323,6 +397,8 @@ rhs(Node *np, Node *ret)
                tmpnode(ret, tp);
                 code(op, ret, &aux1, &aux2);
                 return ret;
+       case OCAST:
+               return cast(tp, rhs(l, &aux1), ret);
        case OASSIG:
                lhs(l, &aux1);
                rhs(r, ret);