32 lines
1.1 KiB
Plaintext
32 lines
1.1 KiB
Plaintext
.include "system.h65"
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.export sleep
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.code
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;********************************************************************************
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; @function sleep
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; @param x: Time to sleep in centiseconds (10^-2s = 10ms)
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; @details
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; Interrupts might change the actual time to finish
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; To be exact, time_cs is in units of 0.010244s
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; @modifies: ARG15
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;********************************************************************************
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.proc sleep
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_VAR_1 = ARG15
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stz _VAR_1
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@loop:
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.repeat 17
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nop ; 2 - i
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.endrepeat
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inc _VAR_1 ; 3 - zp
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bne @loop ; 2/3 - r (2 if not taken, but here most of the time its 3)
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; reaching this takes 256 * (X * 2(nop) + 3(inc) + 3(bne)) - 1(last bne) cycles
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; with X = 17: T1 = (256×(17×2 + 3 +3) − 1) × (1/1MHz) = 0,010 239 s
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dex ; 2 - i
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bne @loop ; 2/3 - r
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; with T1 = for running through VAR_1, one iteration takes
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; T1 + (2(dex) + 3(bne)) × (1/1MHz) = 0,010 244 s
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rts
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; so T = N * 0,010 244 s - (1(last bne) + 4(jsr) + 6(rts)) * (1/1MHz)
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.endproc
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