28 lines
624 B
ArmAsm
28 lines
624 B
ArmAsm
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;;
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;; Official Kernal routine, described in:
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;;
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;; - [RG64] C64 Programmer's Reference Guide - page 291
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;; - [CM64] Compute's Mapping the Commodore 64 - page 232
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;;
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;; CPU registers that has to be preserved (see [RG64]): none
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;;
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rdtim:
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;; Disable interrupts for the duration of the routine, to prevent
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;; jiffy clock update while reeading it's values
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sei
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;; Store the jiffy clock state
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ldy TIME + 0
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ldx TIME + 1
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lda TIME + 2
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;; Enable interrupts. More elegant solution would be pha + sei + ... + pla,
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;; but (checked by running a test program) original ROM routine always
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;; leaves IRQs enabled.
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cli
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rts
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