diff options
Diffstat (limited to 'gdb/i386-dep.c')
| -rw-r--r-- | gdb/i386-dep.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/gdb/i386-dep.c b/gdb/i386-dep.c index 09e7e0d..f3ae993 100644 --- a/gdb/i386-dep.c +++ b/gdb/i386-dep.c @@ -767,6 +767,65 @@ i386_get_frame_setup (pc) return (-1); } +/* Return number of args passed to a frame. + Can return -1, meaning no way to tell. */ + +/* on the 386, the instruction following the call could be: + * popl %ecx - one arg + * addl $imm, %esp - imm/4 args; imm may be 8 or 32 bits + * anything else - zero args + */ + +int +i386_frame_num_args (fi) + struct frame_info fi; +{ + int retpc; + unsigned char op; + struct frame_info *pfi; + + pfi = get_prev_frame_info ((fi)); + if (pfi == 0) + { + /* Note: this can happen if we are looking at the frame for + main, because FRAME_CHAIN_VALID won't let us go into + start. If we have debugging symbols, that's not really + a big deal; it just means it will only show as many arguments + to main as are declared. */ + return -1; + } + else + { + retpc = pfi->pc; + op = read_memory_integer (retpc, 1); + if (op == 0x59) + /* pop %ecx */ + return 1; + else if (op == 0x83) + { + op = read_memory_integer (retpc+1, 1); + if (op == 0xc4) + /* addl $<signed imm 8 bits>, %esp */ + return (read_memory_integer (retpc+2,1)&0xff)/4; + else + return 0; + } + else if (op == 0x81) + { /* add with 32 bit immediate */ + op = read_memory_integer (retpc+1, 1); + if (op == 0xc4) + /* addl $<imm 32>, %esp */ + return read_memory_integer (retpc+2, 4) / 4; + else + return 0; + } + else + { + return 0; + } + } +} + /* * parse the first few instructions of the function to see * what registers were stored. |