From: Christian Groessler <chris@groessler.org>
Date: Fri, 14 Feb 2014 00:40:21 +0000 (+0100)
Subject: Turn off mouse polling interrupt if the mouse hasn't been moved for
X-Git-Tag: V2.15~152^2
X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=refs%2Fpull%2F81%2Fhead;p=cc65

Turn off mouse polling interrupt if the mouse hasn't been moved for
some time. Turn it back on when the mouse is moved again.
Since the polling interrupt runs at a rather high frequency (1kHz),
this saves many processor cycles when the mouse is inactive.
---

diff --git a/libsrc/atari/mou/atrst.s b/libsrc/atari/mou/atrst.s
index 773e171e1..35fd768f3 100644
--- a/libsrc/atari/mou/atrst.s
+++ b/libsrc/atari/mou/atrst.s
@@ -11,6 +11,13 @@
 ; is being built.
 ;
 
+;DEBUG           =       1
+
+DISABLE_TIMEOUT =       30              ; # of vertical blank interrupts after which, if
+                                        ; no mouse motion occurred, the polling IRQ gets
+                                        ; disabled.
+                                        ; VBI frequency is 50Hz for PAL and 60Hz for NTSC
+
         .include        "zeropage.inc"
         .include        "mouse-kernel.inc"
         .include        "atari.inc"
@@ -98,6 +105,10 @@ Buttons:        .res    1               ; Button mask
 XPosWrk:        .res    2
 YPosWrk:        .res    2
 
+irq_enabled:    .res    1               ; flag indicating that the high frequency polling interrupt is enabled
+old_porta_vbi:  .res    1               ; previous PORTA value of the VBI interrupt (IRQ)
+how_long:       .res    1               ; counter for how many VBI interrupts the mouse hasn't been moved
+
 .if .defined (AMIGA_MOUSE) .or .defined (ST_MOUSE)
 dumx:           .res    1
 dumy:           .res    1
@@ -226,10 +237,17 @@ INSTALL:
         sta     AUDF1
         sta     STIMER
 
+.if 0   ; the IRQ will now be dynamically enabled when the mouse is moved
         lda     POKMSK
         ora     #%00000001              ; timer 1 enable
         sta     POKMSK
         sta     IRQEN
+        sta     irq_enabled
+.endif
+
+        lda     PORTA
+        and     #$0f
+        sta     old_porta_vbi
 
 ; Done, return zero (= MOUSE_ERR_OK)
 
@@ -444,23 +462,60 @@ IOCTL:  lda     #<MOUSE_ERR_INV_IOCTL     ; We don't support ioclts for now
 ; MUST return carry clear.
 ;
 
-IRQ:
+IRQ:    lda     PORTA                   ; mouse port contents
+        and     #$0f                    ; check port 1 only
+        ldx     irq_enabled
+        bne     @L1
+
+; IRQ is disabled, check for mouse motion and enable IRQ if mouse motion detected
 
-; Turn mouse polling IRQ back on in case it disabled itself due to CRITIC
-; flag being set.
+        cmp     old_porta_vbi
+        beq     @L3                     ; no motion
+
+; Turn mouse polling IRQ back on
 
         lda     POKMSK
         ora     #%00000001              ; timer 1 enable
         sta     POKMSK
         sta     IRQEN
+        sta     irq_enabled
+        bne     @L3
+        ; not reached
+
+; IRQ is enabled
+
+@L1:    cmp     old_porta_vbi           ; mouse motion since last VBI?
+        sta     old_porta_vbi
+        beq     @L2                     ; no, increment timeout to disable IRQ
+
+        lda     #0
+        sta     how_long                ; yes, reinitialize wait counter
+        beq     @L3
+        ; not reached
+
+@L2:    inc     how_long                ; no motion, increment wait counter
+        lda     how_long
+        cmp     #DISABLE_TIMEOUT        ; timeout?
+        bcc     @L3                     ; no
+
+        lda     #0                      ; yes, turn off IRQ
+        sta     how_long
+
+; no mouse input -- turn IRQ off
+
+        sta     irq_enabled
+        lda     POKMSK
+        and     #%11111110              ; timer 1 disable
+        sta     IRQEN
+        sta     POKMSK
 
 ; Check for a pressed button and place the result into Buttons
 
-        ldx     #0
+@L3:    ldx     #0
         lda     TRIG0                   ; joystick #0 trigger
-        bne     @L0                     ; not pressed
+        bne     @L4                     ; not pressed
         ldx     #MOUSE_BTN_LEFT
-@L0:    stx     Buttons
+@L4:    stx     Buttons
 
         jsr     CPREP
 
@@ -471,20 +526,19 @@ IRQ:
         tax
         cpy     XMin
         sbc     XMin+1
-        bpl     @L2
+        bpl     @L5
         ldy     XMin
         ldx     XMin+1
-        jmp     @L3
-@L2:    txa
+        jmp     @L6
 
+@L5:    txa
         cpy     XMax
         sbc     XMax+1
-        bmi     @L3
+        bmi     @L6
         ldy     XMax
         ldx     XMax+1
-@L3:    sty     XPos
+@L6:    sty     XPos
         stx     XPos+1
-
         tya
         jsr     CMOVEX
 
@@ -495,25 +549,35 @@ IRQ:
         tax
         cpy     YMin
         sbc     YMin+1
-        bpl     @L4
+        bpl     @L7
         ldy     YMin
         ldx     YMin+1
-        jmp     @L5
-@L4:    txa
+        jmp     @L8
 
+@L7:    txa
         cpy     YMax
         sbc     YMax+1
-        bmi     @L5
+        bmi     @L8
         ldy     YMax
         ldx     YMax+1
-@L5:    sty     YPos
+@L8:    sty     YPos
         stx     YPos+1
-
         tya
         jsr     CMOVEY
 
         jsr     CDRAW
 
+.ifdef  DEBUG
+        ; print on upper right corner 'E' or 'D', indicating the IRQ is enabled or disabled
+        ldy     irq_enabled
+        beq     @L9
+        lda     #37                     ; screen code for 'E'
+        .byte   $2c                     ; bit opcode, eats next 2 bytes
+@L9:    lda     #36                     ; screen code for 'D'
+        ldy     #39
+        sta     (SAVMSC),y
+.endif
+
         clc
         rts
 
@@ -721,6 +785,11 @@ disable_me:
         and     #%11111110              ; timer 1 disable
         sta     IRQEN
         sta     POKMSK
+        lda     #0
+        sta     irq_enabled
+        lda     PORTA
+        and     #$0f
+        sta     old_porta_vbi
 .ifdef  __ATARIXL__
         rts
 .else