8080: fix low level signal delivery logic

diff --git a/Kernel/lowlevel-8080.s b/Kernel/lowlevel-8080.s
index ae1edf0..c36793f 100644 (file)
--- a/Kernel/lowlevel-8080.s
+++ b/Kernel/lowlevel-8080.s
@@ -17,26 +17,36 @@ deliver_signals:
 deliver_signals_2:
        mov l,a
        mvi h,0
-       push h
        dad h
        lxi d,U_DATA__U_SIGVEC
        dad d
        mov e,m
        inx h
        mov d,m
+
+       mov c,a         ! save the signal number to pass into the helper
+
+       ! Build the return frame
+       lxi b,signal_return
+       push b
+
        xra a
        sta U_DATA__U_CURSIG
        !
        !       Do we need to zero check de here ?
        !
-       lxi b,signal_return
-       push b
-       xchg
-       ei
+       mov a,d
+       ora e
+       jz signal_return                ! raced
+       !
+       !       Off we go. DE = vector B = signal
+       !
+       !       FIXME: if we ever have 8080 binaries with different load
+       !       addresses we will need to fix this
+       !
+       lhld PROGLOAD+16                ! signal vector
        pchl
-
 signal_return:
-       pop h
        di
        lxi h,0
        dad sp