Fixed the break stuff

git-svn-id: svn://svn.cc65.org/cc65/trunk@1593 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/libsrc/plus4/break.s b/libsrc/plus4/break.s
index c51cc4b07bb21b2e24ace0df67bf7fb1bd1e00e7..52c77127c8f375d275335239eea3424c047926dd 100644 (file)
--- a/libsrc/plus4/break.s
+++ b/libsrc/plus4/break.s
@@ -6,8 +6,8 @@
 ;
 
                .export         _set_brk, _reset_brk
-       .destructor     _reset_brk
        .export         _brk_a, _brk_x, _brk_y, _brk_sr, _brk_pc
+        .import         brk_jmp
 
        .include        "plus4.inc"
 
@@ -19,11 +19,11 @@ _brk_y:             .res    1
 _brk_sr:       .res    1
 _brk_pc:       .res    2
 
-oldvec:        .res    2               ; Old vector
+oldvec:        .res    2               ; Old vector
 
 
 .data
-uservec:       jmp     $FFFF           ; Patched at runtime
+uservec:       jmp     $FFFF           ; Patched at runtime
 
 
 .code
@@ -32,21 +32,12 @@ uservec:            jmp     $FFFF           ; Patched at runtime
 .proc  _set_brk
 
        sta     uservec+1
-       stx     uservec+2       ; Set the user vector
+       stx     uservec+2       ; Set the user vector
 
-       lda     oldvec
-       ora     oldvec+1        ; Did we save the vector already?
-               bne     L1              ; Jump if we installed the handler already
-
-       lda     BRKVec
-       sta     oldvec
-       lda     BRKVec+1
-       sta     oldvec+1        ; Save the old vector
-
-L1:    lda     #<brk_handler   ; Set the break vector to our routine
-       ldx     #>brk_handler
-       sta     BRKVec
-       stx     BRKVec+1
+        lda    #<brk_handler   ; Set the break vector to our routine
+       sta     brk_jmp+1
+               lda     #>brk_handler
+       sta     brk_jmp+2
        rts
 
 .endproc
@@ -55,26 +46,20 @@ L1: lda     #<brk_handler   ; Set the break vector to our routine
 ; Reset the break vector
 .proc  _reset_brk
 
-       lda     oldvec
-       ldx     oldvec+1
-       beq     @L9             ; Jump if vector not installed
-       sta     BRKVec
-       stx     BRKVec+1
-       lda     #$00
-       sta     oldvec          ; Clear the old vector
-       stx     oldvec+1
-@L9:   rts
+        lda     #$00
+        sta     brk_jmp+1
+        sta     brk_jmp+2       ; Reset the vector
+        rts
 
 .endproc
 
 
 
-; Break handler, called if a break occurs
+; Break handler, called if a break occurs. Note: Y is not on the stack!
 
 .proc  brk_handler
 
-       pla
-       sta     _brk_y
+               sty     _brk_y
        pla
        sta     _brk_x
        pla

diff --git a/libsrc/plus4/crt0.s b/libsrc/plus4/crt0.s
index 503d086d552442b155b074b438f36c28a9f2f7bb..a2e33413d57e11e01a01a4f16265ce5d78a00394 100644 (file)
--- a/libsrc/plus4/crt0.s
+++ b/libsrc/plus4/crt0.s
@@ -5,7 +5,9 @@
 ;
 
        .export         _exit
-       .import         initlib, donelib
+        .export         brk_jmp
+
+       .import         condes, initlib, donelib
        .import         push0, _main, zerobss
        .import         __IRQFUNC_TABLE__, __IRQFUNC_COUNT__
 
@@ -13,6 +15,11 @@
        .include        "plus4.inc"
 
 
+; ------------------------------------------------------------------------
+; Constants
+
+IRQInd                 = $500  ; JMP $0000 - used as indirect IRQ vector
+
 ; ------------------------------------------------------------------------
 ; Place the startup code in a special segment to cope with the quirks of
 ; plus/4 banking.
@@ -77,17 +84,44 @@ L1: lda     sp,x
 
        jsr     initlib
 
+; If we have IRQ functions, chain our stub into the IRQ vector
+
+        lda     #<__IRQFUNC_COUNT__
+       beq     NoIRQ1
+       lda     IRQVec
+               ldx     IRQVec+1
+       sta     IRQInd+1
+       stx     IRQInd+2
+       lda     #<IRQStub
+       ldx     #>IRQStub
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
+
 ; Pass an empty command line
 
-               jsr     push0           ; argc
+NoIRQ1: jsr            push0           ; argc
        jsr     push0           ; argv
 
        ldy     #4              ; Argument size
                jsr     _main           ; call the users code
 
-; Call module destructors. This is also the _exit entry.
+; Back from main (this is also the _exit entry). Reset the IRQ vector if
+; we chained it.
 
-_exit: jsr     donelib         ; Run module destructors
+_exit:  lda     #<__IRQFUNC_COUNT__
+       beq     NoIRQ2
+       lda     IRQInd+1
+       ldx     IRQInd+2
+       sei
+       sta     IRQVec
+       stx     IRQVec+1
+       cli
+
+; Run module destructors.
+
+NoIRQ2:        jsr     donelib         ; Run module destructors
 
 ; Restore system stuff
 
@@ -118,29 +152,65 @@ IRQ:    pha
         pha
         tsx                     ; Get the stack pointer
         lda     $0103,x         ; Get the saved status register
-        tax
-        lda     #>irqret        ; Push new return address
+        tax                     ; Save for later
+        and     #$10            ; Test for BRK bit
+        bne     dobreak
+        lda     #>irq_ret       ; Push new return address
         pha
-        lda     #<irqret
+        lda     #<irq_ret
         pha
         txa
         pha
         sta     ENABLE_ROM      ; Switch to ROM
         jmp     ($FFFE)         ; Jump to kernal irq handler
 
-irqret: sta     ENABLE_RAM      ; Switch back to RAM
+irq_ret:
+        sta     ENABLE_RAM      ; Switch back to RAM
         pla
         tax
         pla
         rti
 
+dobreak:
+        lda     brk_jmp+2       ; Check high byte of address
+        beq     nohandler
+        jmp     brk_jmp         ; Jump to the handler
+
+; No break handler installed, jump to ROM
+
+nohandler:
+        tya
+        pha                     ; ROM handler expects Y on stack
+        sta     ENABLE_ROM
+        jmp     (BRKVec)        ; Jump indirect to the break vector
+
+; ------------------------------------------------------------------------
+; Stub for the IRQ chain. Is used only if there are IRQs defined. Needed in
+; low memory because of the banking.
+
+.segment        "LOWCODE"
+
+IRQStub:
+        cld                     ; Just to be sure
+        sta     ENABLE_RAM      ; Switch to RAM
+       ldy     #<(__IRQFUNC_COUNT__*2)
+               lda     #<__IRQFUNC_TABLE__
+       ldx     #>__IRQFUNC_TABLE__
+       jsr     condes                  ; Call the IRQ functions
+       sta     ENABLE_ROM
+               jmp     IRQInd                  ; Jump to the saved IRQ vector
+
 ; ------------------------------------------------------------------------
 ; Data
 
 .data
-zpsave:        .res    zpspace
+zpsave:                .res    zpspace
+
+; BRK handling
+brk_jmp:        jmp     $0000
 
 .bss
-spsave:        .res    1
+spsave:                .res    1
+
 
 

diff --git a/libsrc/plus4/plus4.inc b/libsrc/plus4/plus4.inc
index 680a9611a8c78499850f1a3f86b84358d7e79fa8..b1d67d00f12303e2d73eb4edab5982e5ed240977 100644 (file)
--- a/libsrc/plus4/plus4.inc
+++ b/libsrc/plus4/plus4.inc
@@ -70,7 +70,7 @@ TED_RAMSEL    = $FF3F
 ; ---------------------------------------------------------------------------
 ; RAM/ROM selection addresses
 
-ENABLE_ROM      = $FF3E
-ENABLE_RAM      = $FF3F
+ENABLE_ROM      = TED_ROMSEL
+ENABLE_RAM      = TED_RAMSEL