Would the C code in comments give the same functionality.

Given 20 bit address in ES:DI, calculate index into array of cursor positions in BDA and write row/col derived from offset in DI.

Abs2Vect:   push    ds             push    bx                  ; Preserve non-volatile              push    BDA                 ; Simplifies write into BDA             pop     ds      ; word *Cursor = VideoSeg / 128 - 32              mov     es, ax              ; Get video segment B?00 where ? = (8-F)             mov     bh, al              ; Make sure MSB is NULL             shl     ax, 1             mov     bl, ah              ; BX = VideoSeg / 128             xor     bl, 32              ; High nibble will always be 7 is why this works      ; word Coords = int (Addr/2) / 80 * 256 + (Addr/2) % 80              mov     ax, di              ; Get offset into video page ES             shr     ax, 1               ; Addr /= 2             mov     cx, 80              ; Assume 80 columns / row.             xor     dx, dx             div     cx                  ; AL = int (Addr / 80), DL = Addr % 80             mov     dh, al              ; DX = Row/Col      ; *Cursor = Coords              mov     [bx], dx            ; Update new cursor positon in BDA              pop     bx             pop     ds                  ; Restore non-volatile.             ret 

I tried to find an online compiler that would give disassembly, but didn’t have much luck.