77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
/**
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* Marlin 3D Printer Firmware
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* Copyright (C) 2016 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
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*
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* Based on Sprinter and grbl.
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* Copyright (C) 2011 Camiel Gubbels / Erik van der Zalm
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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/**
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* AVR busy wait delay Cycles routines:
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*
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* DELAY_CYCLES(count): Delay execution in cycles
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* DELAY_NS(count): Delay execution in nanoseconds
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* DELAY_US(count): Delay execution in microseconds
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*/
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#ifndef MARLIN_DELAY_H
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#define MARLIN_DELAY_H
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#define nop() __asm__ __volatile__("nop;\n\t":::)
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FORCE_INLINE static void __delay_4cycles(uint8_t cy) {
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__asm__ __volatile__(
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L("1")
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A("dec %[cnt]")
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A("nop")
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A("brne 1b")
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: [cnt] "+r"(cy) // output: +r means input+output
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: // input:
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: "cc" // clobbers:
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);
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}
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/* ---------------- Delay in cycles */
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FORCE_INLINE static void DELAY_CYCLES(uint16_t x) {
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if (__builtin_constant_p(x)) {
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#define MAXNOPS 4
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if (x <= (MAXNOPS)) {
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switch (x) { case 4: nop(); case 3: nop(); case 2: nop(); case 1: nop(); }
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}
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else {
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const uint32_t rem = (x) % (MAXNOPS);
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switch (rem) { case 3: nop(); case 2: nop(); case 1: nop(); }
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if ((x = (x) / (MAXNOPS)))
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__delay_4cycles(x); // if need more then 4 nop loop is more optimal
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}
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#undef MAXNOPS
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}
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else
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__delay_4cycles(x / 4);
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}
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#undef nop
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/* ---------------- Delay in nanoseconds */
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#define DELAY_NS(x) DELAY_CYCLES( (x) * (F_CPU/1000000L) / 1000L )
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/* ---------------- Delay in microseconds */
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#define DELAY_US(x) DELAY_CYCLES( (x) * (F_CPU/1000000L) )
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#endif // MARLIN_DELAY_H
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