sc108: update to new interrupt rules and fix signal vector bug

diff --git a/Kernel/platform-sc108/sc108.s b/Kernel/platform-sc108/sc108.s
index e6bb0e5..f7ed1f2 100644 (file)
--- a/Kernel/platform-sc108/sc108.s
+++ b/Kernel/platform-sc108/sc108.s
@@ -365,15 +365,30 @@ interrupt_high:
            push af
            push de
            push hl
+           ex af,af'
+           push af
+           push bc
+           exx
+           push bc
+           push de
+           push hl
+           push ix
+           push iy
            ld a,(banknum)
-           ld l,a
+           ld c,a
            ld a,#0x01
            out (0x38),a                ; Bank 0, no ROM
            ld (istack_switched_sp),sp  ; istack is positioned to be valid
            ld sp,#istack_top           ; in both banks. We just have to
-           push hl                     ; save return bank
+           ;
+           ;   interrupt_handler may come back on a different stack in
+           ;   which case bc is junk. Fortuntely we never pre-empt in
+           ;   kernel so the case we care about bc is always safe. This is
+           ;   not a good way to write code and should be fixed! FIXME
+           ;
+           push bc
            call interrupt_handler      ; switch on the right SP
-           pop hl
+           pop bc
            ; Restore stack pointer to user. This leaves us with an invalid
            ; stack pointer if called from user but interrupts are off anyway
            ld sp,(istack_switched_sp)
@@ -389,6 +404,18 @@ interrupt_high:
            xor a
            cp e
            call nz, sigpath
+pops:
+           ex af,af'
+           exx
+           pop iy
+           pop ix
+           pop hl
+           pop de
+           pop bc
+           exx
+           pop bc
+           pop af
+           ex af,af'
            pop hl
            pop de
            pop af
@@ -397,13 +424,9 @@ interrupt_high:
 kernout:
            ; restore bank - if we interrupt mid user copy or similar we
            ; have to put the right bank back
-           ld a,l
+           ld a,c
            out (0x38),a
-           pop hl
-           pop de
-           pop af
-           ei
-           ret
+           jr pops
            
 sigpath:
            push de             ; signal number