Use CC65 runtime for Atari and C64 timer functions
This is just for the "C" interface of IP65. clk_timer.s replaces atr_timer.s (on Atari) and is new for the C64 (there wasn't an implementation for the "C" interface before).
This commit is contained in:
Christian Groessler
parent
673e2da011
commit
afada39f9a
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@ -55,7 +55,8 @@ C64OBJS=\
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cbmcharconv.o
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C64_OBJS=\
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c64timer.o \
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clk_timer.o \
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c64_cps.o \
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c64_input.o
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A2OBJS=\
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@ -82,11 +83,11 @@ ATROBJS=\
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atrcharconv.o
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ATR_OBJS=\
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atr_timer.o \
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clk_timer.o \
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atr_input.o
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ATRXL_OBJS=\
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atr_timer.xl.o \
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clk_timer.xl.o \
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atr_input.xl.o
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VIC20OBJS=\
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@ -1,141 +0,0 @@
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; timer routines
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;
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; the timer should be a 16-bit counter that's incremented by about
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; 1000 units per second. it doesn't have to be particularly accurate.
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.include "atari.inc"
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.include "../inc/common.i"
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.export timer_init
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.export timer_read
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.export timer_seconds
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.import _atexit
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.bss
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current_time_value: .res 2
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current_seconds: .res 1
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current_jiffies: .res 1
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timer_freq: .res 1 ; VBLANK frequency: 50 - PAL, 60 - NTSC
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timer_freq_reciproc:.res 1 ; reciprocal for timer_freq in ms: 20 - PAL, ~17 - NTSC
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.data
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vbichain: .word 0
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.code
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; reset timer to 0 and install handler
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; inputs: none
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; outputs: none
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timer_init:
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lda vbichain+1
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bne @done
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lda PAL ; hardware register describing TV system of GTIA
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and #$0e ; mask out irrelevant bits
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bne @ntsc
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; PAL system
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lda #50
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sta timer_freq
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lda #20
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sta timer_freq_reciproc
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bne @system_set
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@ntsc:
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; NTSC system
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lda #60
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sta timer_freq
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lda #17
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sta timer_freq_reciproc
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@system_set:
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lda #0 ; initialize time variables
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sta current_time_value
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sta current_time_value+1
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sta current_seconds
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sta current_jiffies
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ldax VVBLKI ; IMMEDIATE VERTICAL BLANK NMI VECTOR
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stax vbichain ; save old immediate vector
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ldy #<timer_vbl_handler
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ldx #>timer_vbl_handler
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lda #6 ; STAGE 1 VBI
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jsr SETVBV ; vector to set VBLANK parameters
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@done:
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ldax #timer_exit
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jmp _atexit
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timer_exit:
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lda vbichain+1
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beq @handler_not_installed
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ldy vbichain
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ldx vbichain+1
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lda #6 ; STAGE 1 VBI
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jsr SETVBV ; vector to set VBLANK parameters
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lda #0
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sta vbichain
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sta vbichain+1
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@handler_not_installed:
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rts
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; read the current timer value
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; inputs: none
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; outputs: AX = current timer value (roughly equal to number of milliseconds since the last call to 'timer_init')
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timer_read:
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ldax current_time_value
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rts
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; tick over the current timer value - should be called 50 or 60 times per second, depending on the TV system
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; inputs: none
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; outputs: none (all registers preserved, but carry flag can be modified)
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timer_vbl_handler:
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pha
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lda timer_freq_reciproc ; ms per tick
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clc
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adc current_time_value
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sta current_time_value
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bcc :+
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inc current_time_value+1
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: inc current_jiffies
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lda current_jiffies
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cmp timer_freq ; full second?
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bne @done ; no, we're done
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lda #0 ; yes, increment "seconds" counter
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sta current_jiffies
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sed
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clc
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lda #$01
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adc current_seconds
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cld
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cmp #$60
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bne :+
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lda #$00
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: sta current_seconds
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@done:
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pla
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jmp SYSVBV ; vector to process immediate VBLANK
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timer_seconds:
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lda current_seconds
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rts
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;-- LICENSE FOR atr_timer.s --
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; The contents of this file are subject to the Mozilla Public License
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; Version 1.1 (the "License"); you may not use this file except in
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; compliance with the License. You may obtain a copy of the License at
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; http://www.mozilla.org/MPL/
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;
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; Software distributed under the License is distributed on an "AS IS"
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; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
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; License for the specific language governing rights and limitations
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; under the License.
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;
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; The Original Code is ip65.
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;
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; The Initial Developer of the Original Code is Jonno Downes,
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; jonno@jamtronix.com.
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; Portions created by the Initial Developer are Copyright (C) 2009
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; Jonno Downes. All Rights Reserved.
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; -- LICENSE END --
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@ -0,0 +1,13 @@
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; implementation of __clocks_per_sec for C64
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; CC65's C64 runtime library doesn't provide this function
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; this file provides a version in order that clk_timer.s works without 'ifdefs'
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.export __clocks_per_sec
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.code
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__clocks_per_sec:
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lda #60
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rts
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.end
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@ -0,0 +1,171 @@
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; timer routines
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; this implementation is for Atari and C64.
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; it uses parts of the C runtime library
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;
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; the timer should be a 16-bit counter that's incremented by about
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; 1000 units per second. it doesn't have to be particularly accurate.
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.include "../inc/common.i"
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.export timer_init
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.export timer_read
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.export timer_seconds
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.import __clocks_per_sec, _clock
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.import tosumodeax, tosudiveax
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.import pusheax, incsp4
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.importzp sp, sreg
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.bss
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timer_freq: .res 1 ; VBLANK frequency: 50 - PAL, 60 - NTSC (Atari); always 60 (C64)
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mult_temp: .res 2 ; temp var for multiplication routines
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mult_temp_x:.res 1 ; another temp var for multiplication routines
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.data
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mult: .byte $4C ; JMP opcode
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.res 2 ; address
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.code
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; get timer frequency and patch multiplication routine pointer
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; inputs: none
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; outputs: none
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timer_init:
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jsr __clocks_per_sec
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sta timer_freq
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cmp #50
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beq @timer50
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lda #<mult17
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ldx #>mult17
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bne @timerset ; jmp always
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@timer50:
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lda #<mult20
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ldx #>mult20
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@timerset:
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sta mult+1
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stx mult+2
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rts
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; read the current timer value
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; inputs: none
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; outputs: AX = current timer value in milliseconds
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timer_read = mult
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; get current seconds clock hand
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; inputs: none
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; outputs: A = seconds hand (in BCD, range $00..$59)
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timer_seconds:
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jsr _clock ; return current tick count in sreg:AX (high:low 16bits)
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jsr pusheax ; push tick count onto stack
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ldx #0
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stx sreg
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stx sreg+1
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lda timer_freq
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jsr tosudiveax ; dividend on stack, divisor in sreg:AX
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jsr pusheax
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ldx #0
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stx sreg
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stx sreg+1
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lda #60
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jsr tosumodeax ; result modulo 60
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; convert to BCD, a poor man's conversion here....
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cmp #50
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bcs @rs_50
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cmp #40
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bcs @rs_40
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cmp #30
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bcs @rs_30
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cmp #20
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bcs @rs_20
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cmp #10
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bcs @rs_10
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rts
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@rs_10:
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sbc #10
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ora #$10
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rts
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@rs_20:
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sbc #20
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ora #$20
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rts
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@rs_30:
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sbc #30
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ora #$30
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rts
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@rs_40:
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sbc #40
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ora #$40
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rts
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@rs_50:
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sbc #50
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ora #$50
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rts
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; get the current tick count, multiply it by 20, and return the lower 16 bits
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; x*20 = x*16 + x*4
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; inputs: none
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; outputs: AX - tick count times 20 ('milliseconds')
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mult20:
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jsr _clock ; return current tick count in sreg:AX (high:low 16bits)
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stx mult_temp_x ; remember high byte of lower 16bits
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asl a
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rol mult_temp_x
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asl a
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rol mult_temp_x
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sta mult_temp
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ldx mult_temp_x
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stx mult_temp+1 ; mult_temp = ticks * 4
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asl a
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rol mult_temp_x
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asl a
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rol mult_temp_x ; mult_temp_x:A = 'ticks * 16'
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clc ; AX - tick count * 16, mult_temp - tick count * 4
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adc mult_temp
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sta mult_temp
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lda mult_temp+1
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adc mult_temp_x
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tax
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lda mult_temp
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rts
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; get the current tick count, multiply it by 17, and return the lower 16 bits
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; x*17 = x*16 + x
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; inputs: none
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; outputs: AX - tick count times 17 ('milliseconds')
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mult17:
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jsr _clock ; return current tick count in sreg:AX (high:low 16bits)
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sta mult_temp
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stx mult_temp+1
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stx mult_temp_x
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.repeat 4
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asl a
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rol mult_temp_x
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.endrepeat ; mult_temp_x:A = 'ticks * 16'
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clc
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adc mult_temp
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sta mult_temp
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lda mult_temp+1
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adc mult_temp_x
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tax
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lda mult_temp
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rts
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;-- LICENSE FOR clk_timer.s --
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; The contents of this file are subject to the Mozilla Public License
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; Version 1.1 (the "License"); you may not use this file except in
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; compliance with the License. You may obtain a copy of the License at
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; http://www.mozilla.org/MPL/
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;
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; Software distributed under the License is distributed on an "AS IS"
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; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
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; License for the specific language governing rights and limitations
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; under the License.
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; -- LICENSE END --
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