Refactor macros for accessing Beam instructions

The BeamOp() macro in erl_vm.h is clumsy to use. All users
cast the return value to BeamInstr.

Define new macros that are easier to use. In the future,
we might want to pack an operand into the same word as
the pointer to the instruction, so we will define two macros.

BeamIsOpCode() is used to rewrite code like this:

  if (Instr == (BeamInstr) BeamOp(op_i_func_info_IaaI) {
    ...
  }

to:

  if (BeamIsOpCode(Instr, op_i_func_info_IaaI)) {
    ...
  }

BeamOpCodeAddr(op_apply_bif) is used when we need the address
for an instruction.

Also elimiminate the global variables em_* in beam_emu.c.
They are not really needed. Use the BeamOpCodeAddr() macro
instead.

1 files changed, 7 insertions, 3 deletions

diff --git a/erts/emulator/beam/erl_vm.h b/erts/emulator/beam/erl_vm.h
index 076767c7cd..0e32559f1b 100644
--- a/erts/emulator/beam/erl_vm.h
+++ b/erts/emulator/beam/erl_vm.h
@@ -202,11 +202,15 @@ extern int erts_pd_initial_size;/* Initial Process dictionary table size */
 
 #include "erl_term.h"
 
-#ifdef NO_JUMP_TABLE 
-#define BeamOp(Op) (Op)
+#if defined(NO_JUMP_TABLE)
+#  define BeamOpsAreInitialized() (1)
+#  define BeamOpCodeAddr(OpCode) ((BeamInstr)(OpCode))
 #else
 extern void** beam_ops;
-#define BeamOp(Op) beam_ops[(Op)]
+#  define BeamOpsAreInitialized() (beam_ops != 0)
+#  define BeamOpCodeAddr(OpCode) ((BeamInstr)beam_ops[(OpCode)])
 #endif
 
+#define BeamIsOpCode(InstrWord, OpCode) ((InstrWord) == BeamOpCodeAddr(OpCode))
+
 #endif	/* __ERL_VM_H__ */