From 37107174c61425915b02c5f327cdfe9335da2cae Mon Sep 17 00:00:00 2001 From: Oliver Schmidt Date: Thu, 18 Jun 2020 21:44:42 +0200 Subject: [PATCH] Added waitvsync() for the Enhanced Apple //e. The implementation is a bit tricky as it requires to take different code paths for the //e, the //c and the IIgs. Additionally the //c only provides a VBL IRQ flag supposed to be used by an IRQ handler to determine what triggered the IRQ. However, masking IRQs on the CPU, activating the VBL IRQ, clearing any pending VBL IRQs and then polling for the IRQ flag does the trick. --- asminc/apple2.inc | 40 ++++++++++++++----------- doc/apple2enh.sgml | 3 +- include/apple2enh.h | 3 ++ libsrc/apple2/get_ostype.s | 2 +- libsrc/apple2/waitvsync.s | 60 ++++++++++++++++++++++++++++++++++++++ 5 files changed, 88 insertions(+), 20 deletions(-) create mode 100644 libsrc/apple2/waitvsync.s diff --git a/asminc/apple2.inc b/asminc/apple2.inc index 19906ec2f..5ebf73164 100644 --- a/asminc/apple2.inc +++ b/asminc/apple2.inc @@ -1,6 +1,6 @@ ;----------------------------------------------------------------------------- -; Zero page stuff +; Zero page WNDLFT := $20 ; Text window left WNDWDTH := $21 ; Text window width @@ -31,35 +31,41 @@ PWREDUP := $03F4 ; This must be = EOR #$A5 of SOFTEV+1 KBD := $C000 ; Read keyboard KBDSTRB := $C010 ; Clear keyboard strobe -; 80 column video switches +; 80 column video CLR80COL:= $C000 ; Disable 80 column store SET80COL:= $C001 ; Enable 80 column store RD80COL := $C018 ; >127 if 80 column store enabled RD80VID := $C01F ; >127 if 80 column video enabled -; Character set switches +; Character set CLRALTCHAR := $C00E ; Normal Apple II char set SETALTCHAR := $C00F ; Norm/inv LC, no flash ALTCHARSET := $C01E ; >127 if alt charset switched in -; Language card switches +; Language card RDLCBNK2:= $C011 ; >127 if LC bank 2 in use RDLCRAM := $C012 ; >127 if LC is read enabled ROMIN := $C081 ; Swap in D000-FFFF ROM LCBANK2 := $C083 ; Swap in LC bank 2 LCBANK1 := $C08B ; Swap in LC bank 1 -; Video mode switches -TXTCLR := $C050 ; Display graphics -TXTSET := $C051 ; Display text -MIXCLR := $C052 ; Disable 4 lines of text -MIXSET := $C053 ; Enable 4 lines of text -LOWSCR := $C054 ; Page 1 -HISCR := $C055 ; Page 2 -LORES := $C056 ; Lores graphics -HIRES := $C057 ; Hires graphics -DHIRESON := $C05E ; Enable double-width graphics -DHIRESOFF := $C05F ; Disable double-width graphics +; Vertical blanking +RDVBLBAR := $C019 ; >127 if not vertical blanking +RDVBLMSK := $C041 ; >127 if VBL interrupts enabled +DISVBL := $C05A ; Disable VBL interrupts +ENVBL := $C05B ; Enable VBL interrupts + +; Video mode +TXTCLR := $C050 ; Display graphics +TXTSET := $C051 ; Display text +MIXCLR := $C052 ; Disable 4 lines of text +MIXSET := $C053 ; Enable 4 lines of text +LOWSCR := $C054 ; Page 1 +HISCR := $C055 ; Page 2 +LORES := $C056 ; Lores graphics +HIRES := $C057 ; Hires graphics +DHIRESON := $C05E ; Enable double-width graphics +DHIRESOFF := $C05F ; Disable double-width graphics ; Game controller TAPEIN := $C060 ; Read casette input / Switch input 3 @@ -73,8 +79,8 @@ PADDL3 := $C067 ; Analog input 3 PTRIG := $C070 ; Analog input reset ; Input/Output Unit -IOUDISON := $C07E ; Disable IOU -IOUDISOFF := $C07F ; Enable IOU +IOUDISON := $C07E ; Disable IOU +IOUDISOFF := $C07F ; Enable IOU ; Control Your Apple CYAREG := $C036 ; Bits 0-3=disk detect 4=shadow all banks 7=fast diff --git a/doc/apple2enh.sgml b/doc/apple2enh.sgml index fa70da4ee..2d4381353 100644 --- a/doc/apple2enh.sgml +++ b/doc/apple2enh.sgml @@ -332,10 +332,9 @@ usage. get_ostype rebootafterexit ser_apple2_slot -textframe -textframexy tgi_apple2_mix videomode +waitvsync diff --git a/include/apple2enh.h b/include/apple2enh.h index 3dd8cffc0..58e0b397f 100644 --- a/include/apple2enh.h +++ b/include/apple2enh.h @@ -116,6 +116,9 @@ unsigned __fastcall__ videomode (unsigned mode); ** constants. */ +void waitvsync (void); +/* Wait for start of next frame */ + /* End of apple2enh.h */ diff --git a/libsrc/apple2/get_ostype.s b/libsrc/apple2/get_ostype.s index 71b43d174..a1b1eb5be 100644 --- a/libsrc/apple2/get_ostype.s +++ b/libsrc/apple2/get_ostype.s @@ -4,7 +4,7 @@ ; unsigned char get_ostype (void) ; - .constructor initostype + .constructor initostype, 9 .export _get_ostype ; Identify machine according to: diff --git a/libsrc/apple2/waitvsync.s b/libsrc/apple2/waitvsync.s new file mode 100644 index 000000000..a4ab5ebb3 --- /dev/null +++ b/libsrc/apple2/waitvsync.s @@ -0,0 +1,60 @@ +; +; Oliver Schmidt, 2020-06-14 +; +; void waitvsync (void); +; + .ifdef __APPLE2ENH__ + + .constructor initvsync + .export _waitvsync + .import _get_ostype + + .include "apple2.inc" + + .segment "ONCE" + +initvsync: + jsr _get_ostype + sta ostype + rts + + .code + +_waitvsync: + bit ostype + bmi iigs ; $8x + bvs iic ; $4x + +: bit RDVBLBAR + bpl :- ; Blanking +: bit RDVBLBAR + bmi :- ; Drawing + rts + + ; Apple IIgs TechNote #40, VBL Signal +iigs: bit RDVBLBAR + bmi iigs ; Blanking +: bit RDVBLBAR + bpl :- ; Drawing + rts + + ; Apple IIc TechNote #9, Detecting VBL +iic: sei + sta IOUDISOFF + lda RDVBLMSK + bit ENVBL + bit PTRIG ; Reset VBL interrupt flag +: bit RDVBLBAR + bpl :- + asl + bcs :+ ; VBL interrupts were already enabled + bit DISVBL +: sta IOUDISON ; IIc Tech Ref Man: The firmware normally leaves IOUDIS on. + cli + rts + + .segment "INIT" + +ostype: .res 1 + + .endif ; __APPLE2ENH__