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view OtherSources/data_central_mini.c @ 250:822416168585 bm-2
Buelmann: new implementation for ceiling
Since my first functional fix in the ceiling computation in
commit ceecabfddb57, I noticed that the computation used a
linear search, that became rather computational expensive after
that commit. The simple question is: why not a binary search?
So, this commit implements the binary search. But there is a long
story attached to this. Comparing ceiling results from hwOS and this
OSTC4 code were very different. Basically, the original OSTC4
algorithm computed the ceiling using the same GFlow to GFhigh
slope, in such a way, that the ceiling was in sync with the
presented deco stops, where the hwOS code presents a GFhigh
based ceiling.
This said, it is more logical when the OSTC4 and hwOS code give
similar results. This new recursive algorithm gives very similar
results for the ceiling compared to hwOS.
To be complete here, the Buelmann ceiling is the depth to which
you can ascend, so that the leading tissue reaches GFhigh. This
also explains why the deepest deco stop is normally deeper than
the ceiling (unless one dives with GF like 80/80).
The code implemented here is rather straightforward recursion.
Signed-off-by: Jan Mulder <jlmulder@xs4all.nl>
author | Jan Mulder <jlmulder@xs4all.nl> |
---|---|
date | Thu, 11 Apr 2019 17:48:48 +0200 |
parents | 7801c5d8a562 |
children |
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/** ****************************************************************************** * @copyright heinrichs weikamp * @file data_central_mini.c - bootloader only - * @author heinrichs weikamp gmbh * @date 10-November-2014 * @version V1.0.3 * @since 10-Nov-2014 * @brief * @bug * @warning @verbatim @endverbatim ****************************************************************************** * @attention * * <h2><center>© COPYRIGHT(c) 2015 heinrichs weikamp</center></h2> * ****************************************************************************** */ /* Includes ------------------------------------------------------------------*/ #include <string.h> #include "data_central.h" #include "stm32f4xx_hal.h" #include "crcmodel.h" void translateDate(uint32_t datetmpreg, RTC_DateTypeDef *sDate) { datetmpreg = (uint32_t)(datetmpreg & RTC_DR_RESERVED_MASK); /* Fill the structure fields with the read parameters */ sDate->Year = (uint8_t)((datetmpreg & (RTC_DR_YT | RTC_DR_YU)) >> 16); sDate->Month = (uint8_t)((datetmpreg & (RTC_DR_MT | RTC_DR_MU)) >> 8); sDate->Date = (uint8_t)(datetmpreg & (RTC_DR_DT | RTC_DR_DU)); sDate->WeekDay = (uint8_t)((datetmpreg & (RTC_DR_WDU)) >> 13); /* Convert the date structure parameters to Binary format */ sDate->Year = (uint8_t)RTC_Bcd2ToByte(sDate->Year); sDate->Month = (uint8_t)RTC_Bcd2ToByte(sDate->Month); sDate->Date = (uint8_t)RTC_Bcd2ToByte(sDate->Date); } void translateTime(uint32_t tmpreg, RTC_TimeTypeDef *sTime) { tmpreg = (uint32_t)(tmpreg & RTC_TR_RESERVED_MASK); /* Fill the structure fields with the read parameters */ sTime->Hours = (uint8_t)((tmpreg & (RTC_TR_HT | RTC_TR_HU)) >> 16); sTime->Minutes = (uint8_t)((tmpreg & (RTC_TR_MNT | RTC_TR_MNU)) >>8); sTime->Seconds = (uint8_t)(tmpreg & (RTC_TR_ST | RTC_TR_SU)); sTime->TimeFormat = (uint8_t)((tmpreg & (RTC_TR_PM)) >> 16); /* Convert the time structure parameters to Binary format */ sTime->Hours = (uint8_t)RTC_Bcd2ToByte(sTime->Hours); sTime->Minutes = (uint8_t)RTC_Bcd2ToByte(sTime->Minutes); sTime->Seconds = (uint8_t)RTC_Bcd2ToByte(sTime->Seconds); sTime->SubSeconds = 0; } /* This is derived from crc32b but does table lookup. First the table itself is calculated, if it has not yet been set up. Not counting the table setup (which would probably be a separate function), when compiled to Cyclops with GCC, this function executes in 7 + 13n instructions, where n is the number of bytes in the input message. It should be doable in 4 + 9n instructions. In any case, two of the 13 or 9 instrucions are load byte. This is Figure 14-7 in the text. */ /* http://www.hackersdelight.org/ i guess ;-) *hw */ uint32_t crc32c_checksum(uint8_t* message, uint16_t length, uint8_t* message2, uint16_t length2) { int i, j; uint32_t byte, crc, mask; static unsigned int table[256] = {0}; /* Set up the table, if necessary. */ if (table[1] == 0) { for (byte = 0; byte <= 255; byte++) { crc = byte; for (j = 7; j >= 0; j--) { // Do eight times. mask = -(crc & 1); crc = (crc >> 1) ^ (0xEDB88320 & mask); } table[byte] = crc; } } /* Through with table setup, now calculate the CRC. */ i = 0; crc = 0xFFFFFFFF; while (length--) { byte = message[i]; crc = (crc >> 8) ^ table[(crc ^ byte) & 0xFF]; i = i + 1; } if(length2) { i = 0; while (length2--) { byte = message2[i]; crc = (crc >> 8) ^ table[(crc ^ byte) & 0xFF]; i = i + 1; } } return ~crc; } uint32_t CRC_CalcBlockCRC_moreThan768000(uint32_t *buffer1, uint32_t *buffer2, uint32_t words) { cm_t crc_model; uint32_t word_to_do; uint8_t byte_to_do; int i; // Values for the STM32F generator. crc_model.cm_width = 32; // 32-bit CRC crc_model.cm_poly = 0x04C11DB7; // CRC-32 polynomial crc_model.cm_init = 0xFFFFFFFF; // CRC initialized to 1's crc_model.cm_refin = FALSE; // CRC calculated MSB first crc_model.cm_refot = FALSE; // Final result is not bit-reversed crc_model.cm_xorot = 0x00000000; // Final result XOR'ed with this cm_ini(&crc_model); while (words--) { // The STM32F10x hardware does 32-bit words at a time!!! if(words > (768000/4)) word_to_do = *buffer2++; else word_to_do = *buffer1++; // Do all bytes in the 32-bit word. for (i = 0; i < sizeof(word_to_do); i++) { // We calculate a *byte* at a time. If the CRC is MSB first we // do the next MS byte and vica-versa. if (crc_model.cm_refin == FALSE) { // MSB first. Do the next MS byte. byte_to_do = (uint8_t) ((word_to_do & 0xFF000000) >> 24); word_to_do <<= 8; } else { // LSB first. Do the next LS byte. byte_to_do = (uint8_t) (word_to_do & 0x000000FF); word_to_do >>= 8; } cm_nxt(&crc_model, byte_to_do); } } // Return the final result. return (cm_crc(&crc_model)); } uint32_t CRC_CalcBlockCRC(uint32_t *buffer, uint32_t words) { cm_t crc_model; uint32_t word_to_do; uint8_t byte_to_do; int i; // Values for the STM32F generator. crc_model.cm_width = 32; // 32-bit CRC crc_model.cm_poly = 0x04C11DB7; // CRC-32 polynomial crc_model.cm_init = 0xFFFFFFFF; // CRC initialized to 1's crc_model.cm_refin = FALSE; // CRC calculated MSB first crc_model.cm_refot = FALSE; // Final result is not bit-reversed crc_model.cm_xorot = 0x00000000; // Final result XOR'ed with this cm_ini(&crc_model); while (words--) { // The STM32F10x hardware does 32-bit words at a time!!! word_to_do = *buffer++; // Do all bytes in the 32-bit word. for (i = 0; i < sizeof(word_to_do); i++) { // We calculate a *byte* at a time. If the CRC is MSB first we // do the next MS byte and vica-versa. if (crc_model.cm_refin == FALSE) { // MSB first. Do the next MS byte. byte_to_do = (uint8_t) ((word_to_do & 0xFF000000) >> 24); word_to_do <<= 8; } else { // LSB first. Do the next LS byte. byte_to_do = (uint8_t) (word_to_do & 0x000000FF); word_to_do >>= 8; } cm_nxt(&crc_model, byte_to_do); } } // Return the final result. return (cm_crc(&crc_model)); }