8080: switch to new ABI

diff --git a/Kernel/lowlevel-8080.s b/Kernel/lowlevel-8080.s
index c042e13..11d5ed3 100644 (file)
--- a/Kernel/lowlevel-8080.s
+++ b/Kernel/lowlevel-8080.s
@@ -56,14 +56,10 @@ signal_return:
 unix_syscall_entry:
        di
        push b          ! Must preserve the frame pointer
-       push d          ! will go away when we fix the ABI
        lxi h,6         ! Find arguments on stack frame
 
        dad sp
-       mov a,m
        sta U_DATA__U_CALLNO
-       inx h
-       inx h
        ! Oh for LDIR
        ! Unroll this for speed. Syscall arguments into constant locations
        mov a,m
@@ -130,11 +126,12 @@ unix_return:
        ora l
        jz not_error
        stc
+       ! Carry and errno in HL as expected
        jmp unix_pop
 not_error:
+       ! Retval in HL as the Z80 kernel returns it
        xchg
 unix_pop:
-       pop d
        pop b
        ! ret must directly follow the ei
        ei