Bytecode opcode comments update

This is a cosmetic change only; there is no change in behaviour.

* lisp/emacs-lisp/bytecomp.el:
* src/bytecode.c (BYTE_CODES, exec_byte_code):
Update and/or remove incorrect, outdated or useless comments.
Clarify.  Reorder where appropriate.  Rename Bsave_current_buffer to
Bsave_current_buffer_OBSOLETE and Bsave_current_buffer_1 to
Bsave_current_buffer, reflecting the state since 1996.

1 files changed, 11 insertions, 5 deletions

diff --git a/src/bytecode.c b/src/bytecode.c
index fa068e1ec6b..d75767bb0c5 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -176,8 +176,8 @@ DEFINE (Bmin, 0136)							\
 DEFINE (Bmult, 0137)                                                    \
                                                                         \
 DEFINE (Bpoint, 0140)                                                   \
-/* Was Bmark in v17.  */                                                \
-DEFINE (Bsave_current_buffer, 0141) /* Obsolete.  */                    \
+/* 0141 was Bmark in v17, Bsave_current_buffer in 18-19.  */            \
+DEFINE (Bsave_current_buffer_OBSOLETE, 0141)  /* Obsolete since 20. */  \
 DEFINE (Bgoto_char, 0142)                                               \
 DEFINE (Binsert, 0143)                                                  \
 DEFINE (Bpoint_max, 0144)                                               \
@@ -194,7 +194,7 @@ DEFINE (Bbolp, 0156)							\
 DEFINE (Bbobp, 0157)                                                    \
 DEFINE (Bcurrent_buffer, 0160)                                          \
 DEFINE (Bset_buffer, 0161)                                              \
-DEFINE (Bsave_current_buffer_1, 0162) /* Replacing Bsave_current_buffer.  */ \
+DEFINE (Bsave_current_buffer, 0162)                                     \
 /* 0163 was Bset_mark in v17.  */                                       \
 DEFINE (Binteractive_p, 0164) /* Obsolete since Emacs-24.1.  */         \
                                                                         \
@@ -924,8 +924,8 @@ exec_byte_code (Lisp_Object fun, ptrdiff_t args_template,
           record_unwind_protect_excursion ();
           NEXT;
 
-        CASE (Bsave_current_buffer): /* Obsolete since ??.  */
-        CASE (Bsave_current_buffer_1):
+        CASE (Bsave_current_buffer_OBSOLETE): /* Obsolete since 20.  */
+        CASE (Bsave_current_buffer):
           record_unwind_current_buffer ();
           NEXT;
 
@@ -1678,6 +1678,12 @@ exec_byte_code (Lisp_Object fun, ptrdiff_t args_template,
             /* TODO: Perhaps introduce another byte-code for switch when the
                number of cases is less, which uses a simple vector for linear
                search as the jump table.  */
+
+            /* TODO: Instead of pushing the table in a separate
+               Bconstant op, use an immediate argument (maybe separate
+               switch opcodes for 1-byte and 2-byte constant indices).
+               This would also get rid of some hacks that assume each
+               Bswitch to be preceded by a Bconstant.  */
             Lisp_Object jmp_table = POP;
             if (BYTE_CODE_SAFE && !HASH_TABLE_P (jmp_table))
               emacs_abort ();