IBM 560 - Manual (Page 126)

BIOS Call
Assembler Language: 16-Bit Protected Mode
;
; Build Input Parameter Field
;
mov al, SMB_GET_SYSID
mov [bx].@Func, al
mov ax, offset OutputParm
push ax
mov ax, offset InputParm
push ax
call _SmapiBios
add sp, 4
;
; Get information from Output Parm
;
or ax, ax
jnz Error
mov bx, offset OutputParm
mov al, [bx].@Parm1
A-62 ThinkPad 560/560E SMAPI BIOS