mirror of https://github.com/cc65/cc65.git
45 lines
1.1 KiB
ArmAsm
45 lines
1.1 KiB
ArmAsm
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; Piotr Fusik, 04.11.2001
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; originally by Ullrich von Bassewitz and Sidney Cadot
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;
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; clock_t clock (void);
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; clock_t __clocks_per_sec (void);
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;
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.export _clock, ___clocks_per_sec
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.importzp sreg
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.include "atari.inc"
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.proc _clock
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ldx #5 ; Synchronize with Antic, so the interrupt won't change RTCLOK
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stx WSYNC ; while we're reading it. The synchronization is done same as
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@L1: dex ; in SETVBLV function in Atari OS.
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bne @L1
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stx sreg+1 ; Byte 3 is always zero
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lda RTCLOK+2
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ldx RTCLOK+1
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ldy RTCLOK
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sty sreg
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rts
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.endproc
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.proc ___clocks_per_sec
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ldx #$00 ; Clear byte 1 of return value
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stx sreg ; Clear byte 2 of return value
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stx sreg+1 ; Clear byte 3 of return value
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lda PAL ; Use hw register, PALNTS is only supported on XL/XE ROM
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and #$0e
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bne @NTSC
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lda #50
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rts
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@NTSC: lda #60
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rts
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.endproc
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