Add an operation that checks whether we are at the start of the string.

src/bytecodes-irregexp.h

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 46 matching lines @@
 V(CHECK_LT,          22, 7) /* check_lt uc16 addr32                         */ \
 V(CHECK_GT,          23, 7) /* check_gr uc16 addr32                         */ \
 V(CHECK_NOT_BACK_REF, 24, 6) /* check_not_back_ref capture_idx addr32       */ \
 V(CHECK_NOT_BACK_REF_NO_CASE, 25, 6) /* check_not_back_ref_no_case captu... */ \
 V(CHECK_NOT_REGS_EQUAL, 26, 7) /* check_not_regs_equal reg1 reg2 addr32     */ \
 V(LOOKUP_MAP1,       27, 11) /* l_map1 start16 bit_map_addr32 addr32        */ \
 V(LOOKUP_MAP2,       28, 99) /* l_map2 start16 half_nibble_map_addr32*      */ \
 V(LOOKUP_MAP8,       29, 99) /* l_map8 start16 byte_map addr32*             */ \
 V(LOOKUP_HI_MAP8,    30, 99) /* l_himap8 start8 byte_map_addr32 addr32*     */ \
 V(CHECK_REGISTER_LT, 31, 8) /* check_reg_lt register_index value16 addr32   */ \
-V(CHECK_REGISTER_GE, 32, 8) /* check_reg_ge register_index value16 addr32   */
+V(CHECK_REGISTER_GE, 32, 8) /* check_reg_ge register_index value16 addr32   */ \
+V(CHECK_NOT_AT_START, 33, 5) /* check_not_at_start addr32                   */
 
 #define DECLARE_BYTECODES(name, code, length) \
   static const int BC_##name = code;
 BYTECODE_ITERATOR(DECLARE_BYTECODES)
 #undef DECLARE_BYTECODES
 
 #define DECLARE_BYTECODE_LENGTH(name, code, length) \
   static const int BC_##name##_LENGTH = length;
 BYTECODE_ITERATOR(DECLARE_BYTECODE_LENGTH)
 #undef DECLARE_BYTECODE_LENGTH
 } }
 
 #endif  // V8_BYTECODES_IRREGEXP_H_