BIOS INT 0x15 Function 0x88 always returns same memory size

Question

I'm using BIOS int 0x15 on my Bochs emulator, however this always returns the same memory size (34440) no matter what I have configured:

mov ax, 0x88
int 0x15

I know that there are better methods of memory detection, but I wanted to understand why this wasnt working as expected (just in case there is something I've done wring)

Why is this? Is the bochs bios just hard-coded to return this value?

Answer 1

you may try to check INT 15h, AX=E820h - Query System Address Map how bochs INT15/E820 BIOS-provided physical RAM map

Get Extended Memory Size

mov ah,88h
int 15h