i may know why the gdb command “x” only request one byte each time

I am playing the gdbstub in qemu, i found a bug there http://peter.kingofcoders.com/?p=859 , if i invoke the function cpu_physical_memory_rw(0xffff0, mem_buf, 50, 0) , qemu crashes.

Then, i tested the gdb command “x /20bx 0xffff0” and use tcpflow to capture the gdb packet, i found out gdb send 20 command and each time request one byte only. GDB could already know this bug and try to avoid it by *not* request 20 bytes at once.

gdb x command
gdb x command

read count : 517