mk2: code_part1/OSTC_code_c_part2/p2

comparison code_part1/OSTC_code_c_part2/p2_deco.c @ 317:1de9eee3837b

Minor cleanup in depth convertion for EAD/END.

author	JeanDo
date	Wed, 04 May 2011 11:59:51 +0200
parents	b7e4e74c0e17
children	a99073445c18

comparison

equal deleted inserted replaced

-:48685a69735e
+:1de9eee3837b
 #include "p2_definitions.h"
 #define TEST_MAIN
 #include "shared_definitions.h"
 // Water vapour partial pressure in the lumb.
-#define ppWater 0.0627
+#define ppWater     0.0627
+#define METER_TO_BAR   0.09985
+#define BAR_TO_METER   10.0150      // (1.0/METER_TO_BAR)
 // *************************
 // ** P R O T O T Y P E S **
 // *************************
 //
 static unsigned char calc_nextdecodepth(void)
 {
 //--- Max ascent speed ---------------------------------------------------
 // Recompute leading gas limit, at current depth:
-overlay float depth = (temp_deco - pres_surface) / 0.09985;
+overlay float depth = (temp_deco - pres_surface) * BAR_TO_METER;
 // At most, ascent 1 minute, at 10m/min == 10.0 m.
 overlay float min_depth = (depth > 10.0) ? (depth - 10.0) : 0.0;
 // Do we need to stop at current depth ?
 // Stops are needed ?
 if( sim_lead_tissue_limit > pres_surface )
 {
 // Compute tolerated depth, for the leading tissue [metre]:
-overlay float depth_tol = (sim_lead_tissue_limit - pres_surface) / 0.09985;
+overlay float depth_tol = (sim_lead_tissue_limit - pres_surface) * BAR_TO_METER;
 // Deepest stop, in multiples of 3 metres.
 overlay unsigned char first_stop = 3 * (short)(0.99999 + depth_tol * 0.33333 );
 assert( first_stop < 128 );
 #if defined(__DEBUG) || defined(CROSS_COMPILE)
 {
 // Extra testing code to make sure the first_stop formula
 // and rounding provides correct depth:
-overlay float pres_stop =  first_stop * 0.09985            // Meters to bar
+overlay float pres_stop =  first_stop * METER_TO_BAR
 	                  + pres_surface;
 // Keep GF_low until a first stop depth is found:
 if( first_stop >= low_depth )
 sim_limit( GF_low );
 else if( first_stop == 6 )
 next_stop = char_I_depth_last_deco;
 else
 next_stop = first_stop - 3;             // Index of next (upper) stop.
-	    pres_stop =  next_stop * 0.09985            // Meters to bar
+	    pres_stop =  next_stop * METER_TO_BAR
 	              + pres_surface;
 // Keep GF_low until a first stop depth is found:
 if( next_stop >= low_depth )
 sim_limit( GF_low );
 sim_limit(1.0);
 		pres_gradient = sim_lead_tissue_limit - pres_surface;
 		if (pres_gradient >= 0)
 		{
-			pres_gradient /= 0.29955; 	                            // Bar --> stop number;
+			pres_gradient *= BAR_TO_METER/3;                        // Bar --> stop number;
 			temp_depth_limit = 3 * (short) (pres_gradient + 0.99);  // --> metre : depth for deco
 need_stop = 1;                                          // Hit.
 // Implement last stop at 4m/5m/6m...
 			if( temp_depth_limit == 3 )
 // If there is no gas-switch-delay running ?
 if( sim_gas_delay <= sim_dive_mins)
 {
 // Compute current depth:
-overlay unsigned char depth = (unsigned char)((pres_respiration - pres_surface) / 0.09985);
+overlay unsigned char depth = (unsigned char)((pres_respiration - pres_surface) * BAR_TO_METER);
 assert( depth < 130 );
 // And if I'm above the last decostop (with the 3m margin) ?
 if( (sim_gas_last_depth-3) > depth )
 {
 if( int_temp > 100 *(short)char_I_deco_gas_change[4] )
 	deco_gas_change[4] = char_I_deco_gas_change[4];
 }
 const_ppO2 = char_I_const_ppO2 * 0.01;
-deco_ppO2_change = char_I_deco_ppO2_change / 99.85
+deco_ppO2_change = char_I_deco_ppO2_change * METER_TO_BAR
 + pres_surface
 + float_deco_distance;
 deco_ppO2 = char_I_deco_ppO2 * 0.01;
 float_desaturation_multiplier = char_I_desaturation_multiplier * 0.01;
 float_saturation_multiplier   = char_I_saturation_multiplier   * 0.01;
 		// EAD : Equivalent Air Dive. Equivalent depth for the same N2 level
 		//       with plain air.
 		//       ppN2 = 79% * (P_EAD - ppWater)
 		//       EAD = (P_EAD - Psurface) * 10
 		//   ie: EAD = (ppN2 / 0.7902 + ppWater -Psurface) * 10
-		EAD = (ppN2 / 0.7902 + ppWater - pres_surface) * 9.985;
+		EAD = (ppN2 / 0.7902 + ppWater - pres_surface) * BAR_TO_METER;
 		if( EAD < 0.0 || EAD > 245.5 ) EAD = 0.0;
-		char_O_EAD = (char)(EAD + 0.5);
+		char_O_EAD = (unsigned char)(EAD + 0.5);
 		// END : Equivalent Narcotic Dive.
 		//       Here we count O2 as narcotic too. Hence everything but helium (has a narcosis factor of
 		//       0.23 btw). Hence the formula becomes:
 		//       END * BarPerMeter * (1.0 - 0.0) - ppWater + Psurface == Pambient - ppHe - ppWater
-		//  ie:  END = (Pambient - ppHe - Psurface) * 9.985
+		//  ie:  END = (Pambient - ppHe - Psurface) * BAR_TO_METER
 		//
 		// Source cited:
 		//       The Physiology and Medicine of Diving by Peter Bennett and David Elliott,
 		//       4th edition, 1993, W.B.Saunders Company Ltd, London.
-		END = (pres_respiration - ppHe - pres_surface) * 9.985;
+		END = (pres_respiration - ppHe - pres_surface) * BAR_TO_METER;
 		if( END < 0.0 || END > 245.5 ) END = 0.0;
-		char_O_END = (char)(END  + 0.5);
+		char_O_END = (unsigned char)(END  + 0.5);
 	}
 	else																		// new in v.101
 	{
 		ppN2 = 0.0;                                                             // new in v.101
 		ppHe = 0.0;                                                             // new in v.101
 {
 if( temp_depth_limit == 0 )
 goto Surface;
 //---- We hit a stop at temp_depth_limit ---------------------
-temp_deco = temp_depth_limit * 0.09985      // Convert to relative bar,
+temp_deco = temp_depth_limit * METER_TO_BAR // Convert to relative bar,
 	                      + pres_surface;                   // To absolute.
 update_deco_table();                        // Adds a one minute stops.
 }
 else
 {
 //---- No stop -----------------------------------------------
-temp_deco -= 0.9985;                        // Ascend 10m, no wait.
+temp_deco -= (10*METER_TO_BAR);             // Ascend 10m, no wait.
 //---- Finish computations once surface is reached -----------
 if( temp_deco <= pres_surface )
 {
 Surface:
 //---- Loop until first stop, gas switch, or surface is reached ----------
 	for(;;)
 	{
 // Try ascending 1 full minute.
-	    temp_deco -= 0.9985;        // 1 min, at 10m/min. ~ 1bar.
+	    temp_deco -= 10*METER_TO_BAR;   // 1 min, at 10m/min. ~ 1bar.
 // Compute sim_lead_tissue_limit at GF_low (deepest stop).
 sim_limit(GF_low);
 // Did we reach deepest remaining stop ?
 if( temp_deco < sim_lead_tissue_limit )
 {
-temp_deco += 0.9985;        // Restore last correct depth,
+temp_deco += 10*METER_TO_BAR;   // Restore last correct depth,
-break;                      // End fast ascent.
+break;                          // End fast ascent.
 }
 // Did we reach surface ?
 if( temp_deco <= pres_surface )
 {
 temp_deco = pres_surface;   // Yes: finished !
 break;
 }
 // Check for gas change below new depth ?
-temp_depth_limit = (temp_deco - pres_surface) / 0.09985;
+temp_depth_limit = (temp_deco - pres_surface) * BAR_TO_METER;
 if( gas_switch_deepest() )
 {
-temp_deco = temp_depth_limit * 0.09985 + pres_surface;
+temp_deco = temp_depth_limit * METER_TO_BAR + pres_surface;
 break;
 }
 sim_dive_mins++;                // Advance simulated time by 1 minute.
 sim_alveolar_presures();        // temp_deco --> ppN2/ppHe
 		if( low_depth < 1.5 )
 			rgf = GF_high;
 else
 {
-overlay float temp1 = low_depth * 0.09985;
+overlay float temp1 = low_depth * METER_TO_BAR;
 overlay float temp2 = pres_respiration - pres_surface;
 if (temp2 <= 0)
 			    rgf = GF_high;
 		    else if (temp2 >= temp1)

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comparison code_part1/OSTC_code_c_part2/p2_deco.c @ 317:1de9eee3837b