_REG_EAX
gr[_REG_EAX] = tf->tf_eax;
tf->tf_eax = gr[_REG_EAX];
#define _UC_MACHINE_INTRV(uc) ((uc)->uc_mcontext.__gregs[_REG_EAX])
gdb_regs[ 0] = gregs[_REG_EAX];
gregs[_REG_EAX] = gdb_regs[ 0];