33 lines
639 B
ArmAsm
33 lines
639 B
ArmAsm
#if ROM_LAYOUT_STD || (ROM_LAYOUT_M65 && SEGMENT_KERNAL_0)
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#if CONFIG_IEC
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iec_wait20us:
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// Wait 20usec
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// PAL:
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// - CPU frequency 0.985248 MHz, we need to waste at least 20 cycles
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// NTSC:
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// - CPU frequency 1.022727 MHz, we need to waste at least 21 cycles
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// Waste cycles by reading some unimportant memory location
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// in order not to clutter VICE debug logs
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ora $03FF // 4 cycles
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ora $03FF // 4 cycles
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rts // 6 cycles
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// 6 cycles JSR to routine,
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// 14 cycles routine with RTS
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// 1 cycle to fetch next instruction
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// ---
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// 21 cycles
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#endif // CONFIG_IEC
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#endif // ROM layout
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