NASM: Far Call with Segment and Offset Stored in Registers

Question

I\'ve got the code segment and the offset values stored in two registers, say AX and BX respectively. In NASM how can I encode a far call to AX:B

Answer 1

You have to put them in memory. You can’t perform a far call through registers. Assuming bp is set up as a frame pointer, you can use something like this:

push ax
push bx
call far [bp-N]
add sp, 4

(with a suitable value for N).