Add comment to the top of most .c files explaining their purpose

[p5sagit/p5-mst-13.2.git] / pp_hot.c

diff --git a/pp_hot.c b/pp_hot.c
index b170b3b..98cad17 100644 (file)
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -16,6 +16,19 @@
  *                     Fire, Foes!  Awake!
  */
 
+/* This file contains 'hot' pp ("push/pop") functions that
+ * execute the opcodes that make up a perl program. A typical pp function
+ * expects to find its arguments on the stack, and usually pushes its
+ * results onto the stack, hence the 'pp' terminology. Each OP structure
+ * contains a pointer to the relevant pp_foo() function.
+ *
+ * By 'hot', we mean common ops whose execution speed is critical.
+ * By gathering them together into a single file, we encourage
+ * CPU cache hits on hot code. Also it could be taken as a warning not to
+ * change any code in this file unless you're sure it won't affect
+ * performance.
+ */
+
 #include "EXTERN.h"
 #define PERL_IN_PP_HOT_C
 #include "perl.h"
@@ -2409,7 +2422,7 @@ PP(pp_leavesub)
     PL_curpm = newpm;  /* ... and pop $1 et al */
 
     LEAVESUB(sv);
-    return pop_return();
+    return cx->blk_sub.retop;
 }
 
 /* This duplicates the above code because the above code must not
@@ -2567,7 +2580,7 @@ PP(pp_leavesublv)
     PL_curpm = newpm;  /* ... and pop $1 et al */
 
     LEAVESUB(sv);
-    return pop_return();
+    return cx->blk_sub.retop;
 }
 
 
@@ -2697,9 +2710,9 @@ PP(pp_entersub)
        dMARK;
        register I32 items = SP - MARK;
        AV* padlist = CvPADLIST(cv);
-       push_return(PL_op->op_next);
        PUSHBLOCK(cx, CXt_SUB, MARK);
        PUSHSUB(cx);
+       cx->blk_sub.retop = PL_op->op_next;
        CvDEPTH(cv)++;
        /* XXX This would be a natural place to set C<PL_compcv = cv> so
         * that eval'' ops within this sub know the correct lexical space.