** ** asm.a ** ** Various stuff coded in (Devpac 3) assembler ** ------------------------------------------------------------------------- ** Dummy function. Useful for placing breakpoints in C code. ** (FIXME: remove the dummy function when the rest is working.) SECTION CODE XDEF _dummy _dummy rts ** ------------------------------------------------------------------------- ** Raw keycode message handling SECTION CODE ;C stub: XDEF _rawKey _rawKey ;void rawKey(struct IntuiMessage *) move.l a1,-(a7) move.l 8(a7),a1 bsr rawKey move.l (a7)+,a1 rts INCLUDE "keys.a" ** ------------------------------------------------------------------------- ** Screen updating routines SECTION CODE ;C stubs: XDEF _softScr_Recalc _softScr_Recalc ;void softScr_Recalc(void) movem.l d0-d7/a0-a6,-(a7) bsr softScr_Recalc movem.l (a7)+,d0-d7/a0-a6 rts XDEF _softScr_Redraw _softScr_Redraw ;void softScr_Redraw(void) movem.l d0-d7/a0-a6,-(a7) bsr softScr_Redraw movem.l (a7)+,d0-d7/a0-a6 rts XDEF _softScr_Update _softScr_Update ;void softScr_Update(void) movem.l d0-d7/a0-a6,-(a7) bsr softScr_Update movem.l (a7)+,d0-d7/a0-a6 rts INCLUDE "screen.a" ** ------------------------------------------------------------------------- ** Interrupt server routines: ** Interrupt control structure offsets ** ** Make sure they match the C struct 'intControl' defined in init.c ! RSRESET INTC_Z80_Ctrl rs.l 1 ;Pointer to Z80 control structure INTC_frozen rs.w 1 ;Nonzero if emulation is frozen INTC_INTperiod rs.w 1 ;INT period, in VERTB:s. 0 = off. INTC_INTcount rs.w 1 ;Internal counter INTC_UPDtype rs.w 1 ;Type of update to perform INTC_UPDperiod rs.w 1 ;Screen update period. 0 = off. INTC_UPDcount rs.w 1 ;Internal counter INTC_FLASHstate rs.w 1 ;Flash state, nonzero for inverted. INTC_FLASHperiod rs.w 1 ;Flash period, 25 for 50 Hz VERTB. INTC_FLASHcount rs.w 1 ;Internal counter ;Update types are: ; -1 No update (actually, any negative value). ; 0 Update only changed portions of the screen. ; 1 Complete recalculation and redrawing of bitplanes ; 2 Bitplanes redrawn using cached attribute masks ; 3 Switch to type -1 and signal the control process. ;Types 1 and 2 reset the INTC_UPDtype field to 0 after completing ;the update. Type -1 stays off until changed from the outside. ;Type 3 is for verifying that no update is currently in progress. ** Vertical Blanking Server ** ** D0,D1 scratch. ** See note on A0 if you set priority >= 10, otherwise A0 scratch. ** A1 pointer to data area (specified by is_Data). ** A5 pointer to interrupt code (scratch). A6 scratch. SECTION CODE XDEF _VBServer XREF Z80_INTreq XREF _updateSig XREF _ctrlTaskPtr _VBServer ;Proceed only if emulation is not frozen: tst.w INTC_frozen(a1) bne .vertb_end ;Handle the maskable interrupt: move.w INTC_INTcount(a1),d0 subq.w #1,d0 bne.s .no_signal move.w INTC_INTperiod(a1),d0 ;set count = period beq.s .INT_off ;pretend nothing happened if INT off move.l INTC_Z80_Ctrl(a1),a0 ;get control struct address jsr Z80_INTreq ;No registers are affected. .no_signal move.w d0,INTC_INTcount(a1) .INT_off ;Then the state of the flash attributes: move.w INTC_FLASHcount(a1),d0 subq.w #1,d0 bne.s .no_flash move.w INTC_FLASHperiod(a1),d0 ;set count = period beq.s .flash_off ;flash is off if period is zero move.w INTC_FLASHstate(a1),d1 ;get old state seq d1 ;$FFFF if zero, $0000 if nonzero. ext.w d1 move.w d1,INTC_FLASHstate(a1) ;store new state .no_flash move.w d0,INTC_FLASHcount(a1) .flash_off ;Then the screen updating: move.w INTC_UPDcount(a1),d0 subq.w #1,d0 bne.s .no_update move.w INTC_UPDperiod(a1),d0 ;set count = period beq.s .update_off ;skip the rest if period is zero movem.l d0/d2-d7/a0-a5,-(SP) move.w INTC_FLASHstate(a1),d0 ;wanted flash state in d0 move.w INTC_UPDtype(a1),d1 bmi.s .upd_skip ;no update if type < 0 beq.s .upd_normal ;normal update if type = 0 cmpi.w #1,d1 beq.s .upd_recalc ;recalc if type = 1 cmpi.w #2,d1 beq.s .upd_redraw ;redraw if type = 2 cmpi.w #3,d1 bne.s .upd_skip ;skip if type > 3 ;type 3, switch off and signal: move.w #-1,INTC_UPDtype(a1) ;set type to -1 move.l _updateSig,d0 move.l _ctrlTaskPtr,a1 move.l 4.w,a6 jsr _LVOSignal(a6) ;signal that updating is off bra.s .upd_skip .upd_redraw clr.w INTC_UPDtype(a1) ;reset type bsr softScr_Redraw bra.s .upd_skip .upd_recalc clr.w INTC_UPDtype(a1) ;reset type bsr softScr_Recalc bra.s .upd_skip .upd_normal bsr softScr_Update .upd_skip movem.l (SP)+,d0/d2-d7/a0-a5 .no_update move.w d0,INTC_UPDcount(a1) .update_off ;Return from server: .vertb_end moveq.l #0,d0 ;Set Z - server chain continue rts ** ------------------------------------------------------------------------- ** The code for the separate task running the Z80 emulator: ** ** Can also simply be called as a subroutine, from assembler or C, ** in which case the returned value (in d0) is nonzero upon error and ** zero otherwise. The C prototype is 'int z80task(void)'. ** The control structure pointed to by _Zctrl must be initialised ** before activating this code. ** SECTION DATA _warmStart dc.w 0 ;nonzero to skip Z80_Coldstart call _taskLoop dc.w 0 ;while nonzero, the task will loop XDEF _warmStart XDEF _taskLoop SECTION CODE XDEF z80task XDEF _z80task XREF _resumeSig XREF _Zctrl XREF _ackSig XREF _ctrlTaskPtr XREF _z80TaskPtr INCLUDE "exec/exec.i" INCLUDE "exec/exec_lib.i" INCLUDE "Z80_struct.i" _z80task z80task movem.l a0/a1/a6/d1,-(a7) move.l 4.w,a6 ;Get the 'resume' signal moveq #-1,d0 jsr _LVOAllocSignal(a6) moveq #-1,d1 cmp.l d1,d0 bne .sig_ok bsr z80task_err ;wait until allowed to exit moveq #-1,d0 bra .exit .sig_ok moveq #1,d1 asl.l d0,d1 move.l d1,_resumeSig ;create signal mask ;The initial call can do warm- or coldstart move.l _Zctrl,a0 tst.w _warmStart ;nonzero for warmstart beq.s .cold jsr Z80_Continue bra.s .loop .cold jsr Z80_Coldstart ;The exit/resume loop .loop ;acknowledge the exit and synchronize bsr z80task_sync ;exit if break tst.l d0 bne.s .exit_ok ;else resume emulation move.l _Zctrl,a0 jsr Z80_Continue bra.s .loop .exit_ok moveq #0,d0 .exit clr.l _z80TaskPtr ;clear pointer on self-termination movem.l (a7)+,a0/a1/a6/d1 rts ;This subroutine behaves as if the emulation was running, ;but actually only sends ackSig and waits for signals, ;looping until a break is received. z80task_err .loop bsr z80task_sync tst.l d0 beq.s .loop rts ;This subroutine sends an ackSig, waits for a resume or break ;and then returns, with d0 nonzero if a break was received. ;It assumes that a6 points to ExecBase, and d0/d1,a0/a1 are ;free as scratch registers. z80task_sync ;Send acknowledge signal move.l _ctrlTaskPtr,a1 move.l _ackSig,d0 jsr _LVOSignal(a6) ;Wait for resume or break signal move.l _resumeSig,d0 ori.l #SIGBREAKF_CTRL_C,d0 jsr _LVOWait(a6) ;Make d0 nonzero if break, zero otherwise andi.l #SIGBREAKF_CTRL_C,d0 rts ** ------------------------------------------------------------------------- ** User memory exception handler ** ** A test version: Flashes border and stores passed information. ** Returns if the exception number was 17, ** and otherwise . SECTION DATA ;Storage accessible from C: XDEF _UsrMemH_ExNum XDEF _UsrMemH_Addr XDEF _UsrMemH_Value _UsrMemH_ExNum dc.l 0 _UsrMemH_Addr dc.w 0 _UsrMemH_Value dc.b 0 EVEN SECTION CODE ;d0 contains the exception number (longword, range -128 to 127). ;d1 contains the value (longword, range -128 to 127). ;d2 contains the Z80 address (longword, range -32768 to 32767). ;a0 is scratch (address of user handler). ;All other registers must be protected before used. ;Handler return values: ; d0 (longword) nonzero if value should be written, zero if not. ; d1 (low byte) contains the value. ; d2 and a0 are ignored. XDEF _UsrMemHandler _UsrMemHandler move.l d0,_UsrMemH_ExNum move.b d1,_UsrMemH_Value move.w d2,_UsrMemH_Addr move.w #$F0F,$dff180.l ;set background colour to magenta moveq #17,d2 ;d2 can be used as scratch cmp.w d2,d0 bne.s .ROM ;all attributes but 17 are ROM moveq #1,d0 ;signal 'write' rts .ROM moveq #0,d0 ;signal 'do not write' rts ** -------------------------------------------------------------------------