;----------------------------------------------------------;
; BOS kernel                Christoffer Bubach, 2003-2005. ;
;----------------------------------------------------------;
;                                                          ;
;      Get memory size, only using E801 right now.         ;
;                                                          ;
;----------------------------------------------------------;

;-----------------------------------------;
;  get mem                                ;
;   in:  nothing                          ;
;   out: eax = mem in bytes, 0 = error    ;
;-----------------------------------------;
getmem:
        push   dx
        push   cx
        push   ebx

        xor    eax, eax
        xor    ebx, ebx
        mov    ax, 0xE801
        xor    dx, dx
        xor    cx, cx
        int    0x15
        jnc    .cont1
        xor    eax, eax
        jmp    .end                                   ; failed! :'(

    .cont1:
        mov    si, ax
        or     si, bx
        jne    .cont
        mov    ax, cx
        mov    bx, dx

    .cont:
        cmp    ax, 0x3C00
        jb     .below_16
        movzx  eax, bx
        add    eax, 0x100
        shl    eax, 16                                ; eax = eax * 65536
        jmp    .end

    .below_16:
        shl    eax, 10                                ; eax = eax * 1024

     .end:
        pop    ebx
        pop    cx
        pop    dx
        ret