如何在寄存器内的特定偏移量处打印字符？

Question

I just wanted to know if there was a command within the Unix gdb debugger to print an individual character at a particular offset in the register.

For instance,

If I wanted to know what character of a string was in 0x9(%rdi) how would I display that?

would it be something similar to x/c $rdi,9 ?

Thanks

Answer 1

I guess you need not at an offset "within" a register, but rather you need to read memory pointed to by a register, with a given offset. This can be done this way:

x/c $rdi+9

Generally, the address for the x command is just an expression with a numeric value. The $rdi here is simply the value of the register RDI , to which the constant 9 is added.