code review 81370046: runtime: get rid of most uses of REP for copying/zeroing.

src/liblink/asm6.c

 // Inferno utils/6l/span.c
 // http://code.google.com/p/inferno-os/source/browse/utils/6l/span.c
 //
 //      Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
 //      Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
 //      Portions Copyright © 1997-1999 Vita Nuova Limited
 //      Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
 //      Portions Copyright © 2004,2006 Bruce Ellis
 //      Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
 //      Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
@@ skipping 487 matching lines @@
 static uchar    yloop[] =
 {
         Ynone,  Ybr,    Zloop,  1,
         0
 };
 static uchar    ycall[] =
 {
         Ynone,  Yml,    Zo_m64, 0,
         Yrx,    Yrx,    Zo_m64, 2,
         Ynone,  Ybr,    Zcall,  1,
+        0
+};
+static uchar    yduff[] =
+{
+        Ynone,  Yi32,   Zcall,  1,
         0
 };
 static uchar    yjmp[] =
 {
         Ynone,  Yml,    Zo_m64, 2,
         Ynone,  Ybr,    Zjmp,   1,
         0
 };
 
 static uchar    yfmvd[] =
@@ skipping 994 matching lines @@
 
         { APSHUFD,      yaes2,  Pq,     0x70,(0) },
         { APCLMULQDQ,   yxshuf, Pq, 0x3a,0x44,0 },
 
         { AUSEFIELD,    ynop,   Px, 0,0 },
         { ATYPE },
         { AFUNCDATA,    yfuncdata,      Px, 0,0 },
         { APCDATA,      ypcdata,        Px, 0,0 },
         { ACHECKNIL },
         { AVARDEF },
+        { AVARKILL },
+        { ADUFFCOPY,    yduff,  Px, 0xe8 },
+        { ADUFFZERO,    yduff,  Px, 0xe8 },
 
         { AEND },
         0
 };
 
 static Optab*   opindex[ALAST+1];
 static vlong    vaddr(Link*, Addr*, Reloc*);
 
 // single-instruction no-ops of various lengths.
 // constructed by hand and disassembled with gdb to verify.
@@ skipping 1491 matching lines @@
 
         case Zcall:
                 if(p->to.sym == nil) {
                         ctxt->diag("call without target");
                         sysfatal("bad code");
                 }
                 *ctxt->andptr++ = op;
                 r = addrel(ctxt->cursym);
                 r->off = p->pc + ctxt->andptr - ctxt->and;
                 r->sym = p->to.sym;
+                r->add = p->to.offset;
                 r->type = D_PCREL;
                 r->siz = 4;
                 put4(ctxt, 0);
                 break;
 
         case Zbr:
         case Zjmp:
         case Zloop:
                 // TODO: jump across functions needs reloc
                 if(p->to.sym != nil) {
@@ skipping 434 matching lines @@
                         memmove(ctxt->andptr, naclspfix, sizeof naclspfix);
                         ctxt->andptr += sizeof naclspfix;
                         break;
                 case D_BP:
                         memmove(ctxt->andptr, naclbpfix, sizeof naclbpfix);
                         ctxt->andptr += sizeof naclbpfix;
                         break;
                 }
         }
 }