31b913cddb
The comment behind the ASM MultiU16X8toH16 was misleading. It actually computes ((a<<8)*b)>>16, or (a*b)>>8. Correct the comment and C reference implementation accordingly.
132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
#ifndef SPEED_LOOKUPTABLE_H
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#define SPEED_LOOKUPTABLE_H
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#include "Marlin.h"
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extern const uint16_t speed_lookuptable_fast[256][2] PROGMEM;
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extern const uint16_t speed_lookuptable_slow[256][2] PROGMEM;
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#ifndef _NO_ASM
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// intRes = intIn1 * intIn2 >> 8
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// uses:
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// r26 to store 0
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// r27 to store the byte 1 of the 24 bit result
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#define MultiU16X8toH16(intRes, charIn1, intIn2) \
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asm volatile ( \
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"clr r26 \n\t" \
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"mul %A1, %B2 \n\t" \
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"movw %A0, r0 \n\t" \
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"mul %A1, %A2 \n\t" \
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"add %A0, r1 \n\t" \
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"adc %B0, r26 \n\t" \
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"lsr r0 \n\t" \
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"adc %A0, r26 \n\t" \
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"adc %B0, r26 \n\t" \
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"clr r1 \n\t" \
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: \
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"=&r" (intRes) \
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: \
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"d" (charIn1), \
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"d" (intIn2) \
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: \
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"r26" \
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)
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// intRes = longIn1 * longIn2 >> 24
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// uses:
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// r26 to store 0
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// r27 to store the byte 1 of the 48bit result
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#define MultiU24X24toH16(intRes, longIn1, longIn2) \
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asm volatile ( \
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"clr r26 \n\t" \
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"mul %A1, %B2 \n\t" \
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"mov r27, r1 \n\t" \
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"mul %B1, %C2 \n\t" \
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"movw %A0, r0 \n\t" \
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"mul %C1, %C2 \n\t" \
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"add %B0, r0 \n\t" \
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"mul %C1, %B2 \n\t" \
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"add %A0, r0 \n\t" \
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"adc %B0, r1 \n\t" \
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"mul %A1, %C2 \n\t" \
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"add r27, r0 \n\t" \
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"adc %A0, r1 \n\t" \
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"adc %B0, r26 \n\t" \
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"mul %B1, %B2 \n\t" \
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"add r27, r0 \n\t" \
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"adc %A0, r1 \n\t" \
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"adc %B0, r26 \n\t" \
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"mul %C1, %A2 \n\t" \
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"add r27, r0 \n\t" \
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"adc %A0, r1 \n\t" \
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"adc %B0, r26 \n\t" \
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"mul %B1, %A2 \n\t" \
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"add r27, r1 \n\t" \
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"adc %A0, r26 \n\t" \
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"adc %B0, r26 \n\t" \
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"lsr r27 \n\t" \
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"adc %A0, r26 \n\t" \
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"adc %B0, r26 \n\t" \
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"clr r1 \n\t" \
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: \
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"=&r" (intRes) \
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: \
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"d" (longIn1), \
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"d" (longIn2) \
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: \
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"r26" , "r27" \
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)
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#else //_NO_ASM
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static inline void MultiU16X8toH16(uint16_t& intRes, uint8_t& charIn1, uint16_t& intIn2)
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{
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intRes = ((uint32_t)charIn1 * (uint32_t)intIn2) >> 8;
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}
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static inline void MultiU24X24toH16(uint16_t& intRes, uint32_t& longIn1, uint32_t& longIn2)
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{
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intRes = ((uint64_t)longIn1 * (uint64_t)longIn2) >> 24;
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}
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#endif //_NO_ASM
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FORCE_INLINE unsigned short calc_timer(uint16_t step_rate, uint8_t& step_loops) {
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uint16_t timer;
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if(step_rate > MAX_STEP_FREQUENCY) step_rate = MAX_STEP_FREQUENCY;
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if(step_rate > 20000) { // If steprate > 20kHz >> step 4 times
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step_rate = (step_rate >> 2)&0x3fff;
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step_loops = 4;
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}
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else if(step_rate > 10000) { // If steprate > 10kHz >> step 2 times
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step_rate = (step_rate >> 1)&0x7fff;
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step_loops = 2;
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}
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else {
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step_loops = 1;
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}
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if(step_rate < (F_CPU/500000)) step_rate = (F_CPU/500000);
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step_rate -= (F_CPU/500000); // Correct for minimal speed
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if(step_rate >= (8*256)){ // higher step rate
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unsigned short table_address = (unsigned short)&speed_lookuptable_fast[(unsigned char)(step_rate>>8)][0];
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unsigned char tmp_step_rate = (step_rate & 0x00ff);
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uint16_t gain = (uint16_t)pgm_read_word_near(table_address+2);
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MultiU16X8toH16(timer, tmp_step_rate, gain);
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timer = (unsigned short)pgm_read_word_near(table_address) - timer;
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}
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else { // lower step rates
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unsigned short table_address = (unsigned short)&speed_lookuptable_slow[0][0];
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table_address += ((step_rate)>>1) & 0xfffc;
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timer = (unsigned short)pgm_read_word_near(table_address);
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timer -= (((unsigned short)pgm_read_word_near(table_address+2) * (unsigned char)(step_rate & 0x0007))>>3);
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}
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if(timer < 100) { timer = 100; }//(20kHz this should never happen)////MSG_STEPPER_TOO_HIGH c=0 r=0
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return timer;
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}
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#endif
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