Calling Convention

Overview

Aspect	Convention
Parameter passing	Stack, right-to-left (C convention)
Evaluation order	Right-to-left (two-pass fseek, no reversal step)
Stack cleanup	Caller cleans
Return value	HL (Z80/8080/8085) / AX (8086)

Z80 Stack Frame

Higher addresses:
    [param N]        ← ix+4+N*2 (rightmost on stack)
    ...
    [param 0]        ← ix+4  (leftmost in source)
    [return addr]    ← ix+2
    [saved ix]       ← ix+0  (IX points here)
    [local 0]        ← ix-2
    [local 1]        ← ix-4
    ...
Lower addresses (SP):

8086 Stack Frame

Higher addresses:
    [param N]        ← bp+4+N*2 (or +4+N*4 for far)
    ...
    [param 0]        ← bp+4
    [return addr]    ← bp+2
    [saved bp]       ← bp+0  (BP points here)
    [local 0]        ← bp-2
    [local 1]        ← bp-4
Lower addresses (SP):

Caller Cleanup

Target	Cleanup Code
Z80	`ex de,hl; ld hl,N*2; add hl,sp; ld sp,hl; ex de,hl`
8086	`add sp, N2` (near) / `add sp, N4` (far)
8080	`xchg; lxi h,N*2; dad sp; sphl; xchg`