IBM 560 - Manual (Page 73)

Calling Convention Pseudo Code
The following describes the calling convention using pseudo code.
Assembler Language
InputParm SMB_INPARM < >
OutputParm SMB_OUTPARM < >
16-bit
push ds
mov ax, offset OutputParm
push ax
push ds
mov ax, offset InputParm
push ax
call dword ptr SmapiBios
add sp, 8
32-bit
push ds
mov eax, offset OutputParm
push eax
push ds
mov eax, offset InputParm
push eax
call fword ptr SmapiBios
add sp, 16
ThinkPad 560/560E SMAPI BIOS A-9