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/**
* Marlin 3D Printer Firmware
* Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
*
* Based on Sprinter and grbl.
* Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
*/
#pragma once
/**
* Optimized math functions for AVR
*/
// intRes = longIn1 * longIn2 >> 24
// uses:
// A[tmp] to store 0
// B[tmp] to store bits 16-23 of the 48bit result. The top bit is used to round the two byte result.
// note that the lower two bytes and the upper byte of the 48bit result are not calculated.
// this can cause the result to be out by one as the lower bytes may cause carries into the upper ones.
// B A are bits 24-39 and are the returned value
// C B A is longIn1
// D C B A is longIn2
//
static FORCE_INLINE uint16_t MultiU24X32toH16(uint32_t longIn1, uint32_t longIn2) {
uint8_t tmp1;
uint8_t tmp2;
uint16_t intRes;
__asm__ __volatile__(
A("clr %[tmp1]")
A("mul %A[longIn1], %B[longIn2]")
A("mov %[tmp2], r1")
A("mul %B[longIn1], %C[longIn2]")
A("movw %A[intRes], r0")
A("mul %C[longIn1], %C[longIn2]")
A("add %B[intRes], r0")
A("mul %C[longIn1], %B[longIn2]")
A("add %A[intRes], r0")
A("adc %B[intRes], r1")
A("mul %A[longIn1], %C[longIn2]")
A("add %[tmp2], r0")
A("adc %A[intRes], r1")
A("adc %B[intRes], %[tmp1]")
A("mul %B[longIn1], %B[longIn2]")
A("add %[tmp2], r0")
A("adc %A[intRes], r1")
A("adc %B[intRes], %[tmp1]")
A("mul %C[longIn1], %A[longIn2]")
A("add %[tmp2], r0")
A("adc %A[intRes], r1")
A("adc %B[intRes], %[tmp1]")
A("mul %B[longIn1], %A[longIn2]")
A("add %[tmp2], r1")
A("adc %A[intRes], %[tmp1]")
A("adc %B[intRes], %[tmp1]")
A("lsr %[tmp2]")
A("adc %A[intRes], %[tmp1]")
A("adc %B[intRes], %[tmp1]")
A("mul %D[longIn2], %A[longIn1]")
A("add %A[intRes], r0")
A("adc %B[intRes], r1")
A("mul %D[longIn2], %B[longIn1]")
A("add %B[intRes], r0")
A("clr r1")
: [intRes] "=&r" (intRes),
[tmp1] "=&r" (tmp1),
[tmp2] "=&r" (tmp2)
: [longIn1] "d" (longIn1),
[longIn2] "d" (longIn2)
: "cc"
);
return intRes;
}
// intRes = intIn1 * intIn2 >> 16
// uses:
// r26 to store 0
// r27 to store the byte 1 of the 24 bit result
static FORCE_INLINE uint16_t MultiU16X8toH16(uint8_t charIn1, uint16_t intIn2) {
uint8_t tmp;
uint16_t intRes;
__asm__ __volatile__ (
A("clr %[tmp]")
A("mul %[charIn1], %B[intIn2]")
A("movw %A[intRes], r0")
A("mul %[charIn1], %A[intIn2]")
A("add %A[intRes], r1")
A("adc %B[intRes], %[tmp]")
A("lsr r0")
A("adc %A[intRes], %[tmp]")
A("adc %B[intRes], %[tmp]")
A("clr r1")
: [intRes] "=&r" (intRes),
[tmp] "=&r" (tmp)
: [charIn1] "d" (charIn1),
[intIn2] "d" (intIn2)
: "cc"
);
return intRes;
}
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