Stub in callee save registers.

    Don't enable them since they're broken, but stub them in.

3 files changed, 48 insertions, 3 deletions

diff --git a/6/asm.h b/6/asm.h
index 8decfbf..6eebb0a 100644
--- a/6/asm.h
+++ b/6/asm.h
@@ -4,7 +4,7 @@
 #define Wordsz 4                /* the size of a "natural int" */
 #define Ptrsz 8                 /* the size of a machine word (ie, pointer size) */
 #define K 14                    /* the number of allocatable registers */
-#define Nsaved 14               /* number of registers saved in the ABI */
+#define Nsaved 13               /* number of registers saved in the ABI */
 
 typedef size_t regid;
 
@@ -195,7 +195,6 @@ void locprint(FILE *fd, Loc *l, char spec);
 void iprintf(FILE *fd, Insn *insn);
 
 /* emitting instructions */
-void g(Isel *s, AsmOp op, ...);
 Insn *mkinsn(AsmOp op, ...);
 
 /* register allocation */
diff --git a/6/isel.c b/6/isel.c
index 4cc9444..aa97bc0 100644
--- a/6/isel.c
+++ b/6/isel.c
@@ -131,7 +131,18 @@ static Insn *mkinsnv(AsmOp op, va_list ap)
     return i;
 }
 
-static void g(Isel *s, AsmOp op, ...)
+Insn *mkinsn(AsmOp op, ...)
+{
+    va_list ap;
+    Insn *i;
+
+    va_start(ap, op);
+    i = mkinsnv(op, ap);
+    va_end(ap);
+    return i;
+}
+
+void g(Isel *s, AsmOp op, ...)
 {
     va_list ap;
     Insn *i;
@@ -749,18 +760,44 @@ static void isel(Isel *s, Node *n)
     }
 }
 
+Reg savedregs[] = {
+    Rrcx,
+    Rrdx,
+    Rrbx,
+    Rrsi,
+    Rrdi,
+    Rr8,
+    Rr9,
+    Rr10,
+    Rr11,
+    Rr12,
+    Rr13,
+    Rr14,
+    Rr15
+};
+
 static void prologue(Isel *s, size_t sz)
 {
     Loc *rsp;
     Loc *rbp;
     Loc *stksz;
+    //size_t i;
 
     rsp = locphysreg(Rrsp);
     rbp = locphysreg(Rrbp);
     stksz = loclit(sz, ModeQ);
+    /* enter function */
     g(s, Ipush, rbp, NULL);
     g(s, Imov, rsp, rbp, NULL);
     g(s, Isub, stksz, rsp, NULL);
+#if 0
+    /* save registers */
+    for (i = 0; i < sizeof(savedregs)/sizeof(savedregs[0]); i++) {
+        s->calleesave[i] = locreg(ModeQ);
+        g(s, Imov, locphysreg(savedregs[i]), s->calleesave[i], NULL);
+    }
+#endif
+
     s->stksz = stksz; /* need to update if we spill */
 }
 
@@ -768,6 +805,7 @@ static void epilogue(Isel *s)
 {
     Loc *rsp, *rbp;
     Loc *ret;
+    //size_t i;
 
     rsp = locphysreg(Rrsp);
     rbp = locphysreg(Rrbp);
@@ -775,6 +813,12 @@ static void epilogue(Isel *s)
         ret = loc(s, s->ret);
         g(s, Imov, ret, coreg(Rax, ret->mode), NULL);
     }
+#if 0
+    /* restore registers */
+    for (i = 0; i < Nsaved; i++)
+        g(s, Imov, s->calleesave[i], locphysreg(savedregs[i]), NULL);
+    /* leave function */
+#endif
     g(s, Imov, rbp, rsp, NULL);
     g(s, Ipop, rbp, NULL);
     g(s, Iret, NULL);
diff --git a/6/ra.c b/6/ra.c
index d1f13a2..6373b7d 100644
--- a/6/ra.c
+++ b/6/ra.c
@@ -996,8 +996,10 @@ void regalloc(Isel *s)
     s->prepainted = mkbs();
     s->shouldspill = mkbs();
     s->neverspill = mkbs();
+#if 0
     for (i = 0; i < Nsaved; i++)
         bsput(s->shouldspill, s->calleesave[i]->reg.id);
+#endif
     for (i = 0; i < maxregid; i++)
         if (locmap[i]->reg.colour)
             bsput(s->prepainted, i);