vcgencmd shows wrong memory for ARM

I have the RPI 4 / 8GB RAM wtih all latest updates. The vcgencmd gives wrong memory amount for ARM CPU.

root@DietPi:/home/dietpi/pigpio# vcgencmd get_mem arm
arm=768M               <============================== It should be ~ 7633 M

root@DietPi:/home/dietpi/pigpio# vcgencmd get_mem gpu
gpu=256M

root@DietPi:/home/dietpi/pigpio# cat /proc/meminfo  | grep -i Total
MemTotal:        7816560 kB

root@DietPi:/home/dietpi/pigpio# uname -a
Linux DietPi 5.10.60-v8+ #1449 SMP PREEMPT Wed Aug 25 15:01:33 BST 2021 aarch64 GNU/Linux

Thanks,
Eric