diff options
Diffstat (limited to 'gdb/i960-tdep.c')
| -rw-r--r-- | gdb/i960-tdep.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/gdb/i960-tdep.c b/gdb/i960-tdep.c index 081ad6f..5b7f477 100644 --- a/gdb/i960-tdep.c +++ b/gdb/i960-tdep.c @@ -760,6 +760,53 @@ next_insn (memaddr, pword1, pword2) return 0; } +/* 'start_frame' is a variable in the MON960 runtime startup routine + that contains the frame pointer of the 'start' routine (the routine + that calls 'main'). By reading its contents out of remote memory, + we can tell where the frame chain ends: backtraces should halt before + they display this frame. */ + +int +mon960_frame_chain_valid (chain, curframe) + unsigned int chain; + struct frame_info *curframe; +{ + struct symbol *sym; + struct minimal_symbol *msymbol; + + /* crtmon960.o is an assembler module that is assumed to be linked + * first in an i80960 executable. It contains the true entry point; + * it performs startup up initialization and then calls 'main'. + * + * 'sf' is the name of a variable in crtmon960.o that is set + * during startup to the address of the first frame. + * + * 'a' is the address of that variable in 80960 memory. + */ + static char sf[] = "start_frame"; + CORE_ADDR a; + + + chain &= ~0x3f; /* Zero low 6 bits because previous frame pointers + contain return status info in them. */ + if ( chain == 0 ){ + return 0; + } + + sym = lookup_symbol(sf, 0, VAR_NAMESPACE, (int *)NULL, + (struct symtab **)NULL); + if ( sym != 0 ){ + a = SYMBOL_VALUE (sym); + } else { + msymbol = lookup_minimal_symbol (sf, NULL, NULL); + if (msymbol == NULL) + return 0; + a = SYMBOL_VALUE_ADDRESS (msymbol); + } + + return ( chain != read_memory_integer(a,4) ); +} + void _initialize_i960_tdep () { |