Bug Summary

File:dev/pci/drm/amd/pm/powerplay/hwmgr/ppevvmath.h
Warning:line 339, column 2
Value stored to 'Y_LessThanOne' is never read

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ppatomctrl.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model static -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -ffreestanding -mcmodel=kernel -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -target-feature -sse2 -target-feature -sse -target-feature -3dnow -target-feature -mmx -target-feature +save-args -disable-red-zone -no-implicit-float -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -nostdsysteminc -nobuiltininc -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/sys -I /usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -I /usr/src/sys/arch -I /usr/src/sys/dev/pci/drm/include -I /usr/src/sys/dev/pci/drm/include/uapi -I /usr/src/sys/dev/pci/drm/amd/include/asic_reg -I /usr/src/sys/dev/pci/drm/amd/include -I /usr/src/sys/dev/pci/drm/amd/amdgpu -I /usr/src/sys/dev/pci/drm/amd/display -I /usr/src/sys/dev/pci/drm/amd/display/include -I /usr/src/sys/dev/pci/drm/amd/display/dc -I /usr/src/sys/dev/pci/drm/amd/display/amdgpu_dm -I /usr/src/sys/dev/pci/drm/amd/pm/inc -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu11 -I /usr/src/sys/dev/pci/drm/amd/pm/swsmu/smu12 -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/hwmgr -I /usr/src/sys/dev/pci/drm/amd/pm/powerplay/smumgr -I /usr/src/sys/dev/pci/drm/amd/display/dc/inc -I /usr/src/sys/dev/pci/drm/amd/display/dc/inc/hw -I /usr/src/sys/dev/pci/drm/amd/display/dc/clk_mgr -I /usr/src/sys/dev/pci/drm/amd/display/modules/inc -I /usr/src/sys/dev/pci/drm/amd/display/modules/hdcp -I /usr/src/sys/dev/pci/drm/amd/display/dmub/inc -I /usr/src/sys/dev/pci/drm/i915 -D DDB -D DIAGNOSTIC -D KTRACE -D ACCOUNTING -D KMEMSTATS -D PTRACE -D POOL_DEBUG -D CRYPTO -D SYSVMSG -D SYSVSEM -D SYSVSHM -D UVM_SWAP_ENCRYPT -D FFS -D FFS2 -D FFS_SOFTUPDATES -D UFS_DIRHASH -D QUOTA -D EXT2FS -D MFS -D NFSCLIENT -D NFSSERVER -D CD9660 -D UDF -D MSDOSFS -D FIFO -D FUSE -D SOCKET_SPLICE -D TCP_ECN -D TCP_SIGNATURE -D INET6 -D IPSEC -D PPP_BSDCOMP -D PPP_DEFLATE -D PIPEX -D MROUTING -D MPLS -D BOOT_CONFIG -D USER_PCICONF -D APERTURE -D MTRR -D NTFS -D HIBERNATE -D PCIVERBOSE -D USBVERBOSE -D WSDISPLAY_COMPAT_USL -D WSDISPLAY_COMPAT_RAWKBD -D WSDISPLAY_DEFAULTSCREENS=6 -D X86EMU -D ONEWIREVERBOSE -D MULTIPROCESSOR -D MAXUSERS=80 -D _KERNEL -D CONFIG_DRM_AMD_DC_DCN3_0 -O2 -Wno-pointer-sign -Wno-address-of-packed-member -Wno-constant-conversion -Wno-unused-but-set-variable -Wno-gnu-folding-constant -fdebug-compilation-dir=/usr/src/sys/arch/amd64/compile/GENERIC.MP/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -o /usr/obj/sys/arch/amd64/compile/GENERIC.MP/scan-build/2022-01-12-131800-47421-1 -x c /usr/src/sys/dev/pci/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c
1/*
2 * Copyright 2015 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 */
23#include <asm/div64.h>
24
25#define SHIFT_AMOUNT16 16 /* We multiply all original integers with 2^SHIFT_AMOUNT to get the fInt representation */
26
27#define PRECISION5 5 /* Change this value to change the number of decimal places in the final output - 5 is a good default */
28
29#define SHIFTED_2(2 << 16) (2 << SHIFT_AMOUNT16)
30#define PPMAX(1 << (16 - 1)) - 1 (1 << (SHIFT_AMOUNT16 - 1)) - 1 /* 32767 - Might change in the future */
31
32/* -------------------------------------------------------------------------------
33 * NEW TYPE - fINT
34 * -------------------------------------------------------------------------------
35 * A variable of type fInt can be accessed in 3 ways using the dot (.) operator
36 * fInt A;
37 * A.full => The full number as it is. Generally not easy to read
38 * A.partial.real => Only the integer portion
39 * A.partial.decimal => Only the fractional portion
40 */
41typedef union _fInt {
42 int full;
43 struct _partial {
44 unsigned int decimal: SHIFT_AMOUNT16; /*Needs to always be unsigned*/
45 int real: 32 - SHIFT_AMOUNT16;
46 } partial;
47} fInt;
48
49/* -------------------------------------------------------------------------------
50 * Function Declarations
51 * -------------------------------------------------------------------------------
52 */
53static fInt ConvertToFraction(int); /* Use this to convert an INT to a FINT */
54static fInt Convert_ULONG_ToFraction(uint32_t); /* Use this to convert an uint32_t to a FINT */
55static fInt GetScaledFraction(int, int); /* Use this to convert an INT to a FINT after scaling it by a factor */
56static int ConvertBackToInteger(fInt); /* Convert a FINT back to an INT that is scaled by 1000 (i.e. last 3 digits are the decimal digits) */
57
58static fInt fNegate(fInt); /* Returns -1 * input fInt value */
59static fInt fAdd (fInt, fInt); /* Returns the sum of two fInt numbers */
60static fInt fSubtract (fInt A, fInt B); /* Returns A-B - Sometimes easier than Adding negative numbers */
61static fInt fMultiply (fInt, fInt); /* Returns the product of two fInt numbers */
62static fInt fDivide (fInt A, fInt B); /* Returns A/B */
63static fInt fGetSquare(fInt); /* Returns the square of a fInt number */
64static fInt fSqrt(fInt); /* Returns the Square Root of a fInt number */
65
66static int uAbs(int); /* Returns the Absolute value of the Int */
67static int uPow(int base, int exponent); /* Returns base^exponent an INT */
68
69static void SolveQuadracticEqn(fInt, fInt, fInt, fInt[]); /* Returns the 2 roots via the array */
70static bool_Bool Equal(fInt, fInt); /* Returns true if two fInts are equal to each other */
71static bool_Bool GreaterThan(fInt A, fInt B); /* Returns true if A > B */
72
73static fInt fExponential(fInt exponent); /* Can be used to calculate e^exponent */
74static fInt fNaturalLog(fInt value); /* Can be used to calculate ln(value) */
75
76/* Fuse decoding functions
77 * -------------------------------------------------------------------------------------
78 */
79static fInt fDecodeLinearFuse(uint32_t fuse_value, fInt f_min, fInt f_range, uint32_t bitlength);
80static fInt fDecodeLogisticFuse(uint32_t fuse_value, fInt f_average, fInt f_range, uint32_t bitlength);
81static fInt fDecodeLeakageID (uint32_t leakageID_fuse, fInt ln_max_div_min, fInt f_min, uint32_t bitlength);
82
83/* Internal Support Functions - Use these ONLY for testing or adding to internal functions
84 * -------------------------------------------------------------------------------------
85 * Some of the following functions take two INTs as their input - This is unsafe for a variety of reasons.
86 */
87static fInt Divide (int, int); /* Divide two INTs and return result as FINT */
88static fInt fNegate(fInt);
89
90static int uGetScaledDecimal (fInt); /* Internal function */
91static int GetReal (fInt A); /* Internal function */
92
93/* -------------------------------------------------------------------------------------
94 * TROUBLESHOOTING INFORMATION
95 * -------------------------------------------------------------------------------------
96 * 1) ConvertToFraction - InputOutOfRangeException: Only accepts numbers smaller than MAX (default: 32767)
97 * 2) fAdd - OutputOutOfRangeException: Output bigger than MAX (default: 32767)
98 * 3) fMultiply - OutputOutOfRangeException:
99 * 4) fGetSquare - OutputOutOfRangeException:
100 * 5) fDivide - DivideByZeroException
101 * 6) fSqrt - NegativeSquareRootException: Input cannot be a negative number
102 */
103
104/* -------------------------------------------------------------------------------------
105 * START OF CODE
106 * -------------------------------------------------------------------------------------
107 */
108static fInt fExponential(fInt exponent) /*Can be used to calculate e^exponent*/
109{
110 uint32_t i;
111 bool_Bool bNegated = false0;
112
113 fInt fPositiveOne = ConvertToFraction(1);
114 fInt fZERO = ConvertToFraction(0);
115
116 fInt lower_bound = Divide(78, 10000);
117 fInt solution = fPositiveOne; /*Starting off with baseline of 1 */
118 fInt error_term;
119
120 static const uint32_t k_array[11] = {55452, 27726, 13863, 6931, 4055, 2231, 1178, 606, 308, 155, 78};
121 static const uint32_t expk_array[11] = {2560000, 160000, 40000, 20000, 15000, 12500, 11250, 10625, 10313, 10156, 10078};
122
123 if (GreaterThan(fZERO, exponent)) {
124 exponent = fNegate(exponent);
125 bNegated = true1;
126 }
127
128 while (GreaterThan(exponent, lower_bound)) {
129 for (i = 0; i < 11; i++) {
130 if (GreaterThan(exponent, GetScaledFraction(k_array[i], 10000))) {
131 exponent = fSubtract(exponent, GetScaledFraction(k_array[i], 10000));
132 solution = fMultiply(solution, GetScaledFraction(expk_array[i], 10000));
133 }
134 }
135 }
136
137 error_term = fAdd(fPositiveOne, exponent);
138
139 solution = fMultiply(solution, error_term);
140
141 if (bNegated)
142 solution = fDivide(fPositiveOne, solution);
143
144 return solution;
145}
146
147static fInt fNaturalLog(fInt value)
148{
149 uint32_t i;
150 fInt upper_bound = Divide(8, 1000);
151 fInt fNegativeOne = ConvertToFraction(-1);
152 fInt solution = ConvertToFraction(0); /*Starting off with baseline of 0 */
153 fInt error_term;
154
155 static const uint32_t k_array[10] = {160000, 40000, 20000, 15000, 12500, 11250, 10625, 10313, 10156, 10078};
156 static const uint32_t logk_array[10] = {27726, 13863, 6931, 4055, 2231, 1178, 606, 308, 155, 78};
157
158 while (GreaterThan(fAdd(value, fNegativeOne), upper_bound)) {
159 for (i = 0; i < 10; i++) {
160 if (GreaterThan(value, GetScaledFraction(k_array[i], 10000))) {
161 value = fDivide(value, GetScaledFraction(k_array[i], 10000));
162 solution = fAdd(solution, GetScaledFraction(logk_array[i], 10000));
163 }
164 }
165 }
166
167 error_term = fAdd(fNegativeOne, value);
168
169 return (fAdd(solution, error_term));
170}
171
172static fInt fDecodeLinearFuse(uint32_t fuse_value, fInt f_min, fInt f_range, uint32_t bitlength)
173{
174 fInt f_fuse_value = Convert_ULONG_ToFraction(fuse_value);
175 fInt f_bit_max_value = Convert_ULONG_ToFraction((uPow(2, bitlength)) - 1);
176
177 fInt f_decoded_value;
178
179 f_decoded_value = fDivide(f_fuse_value, f_bit_max_value);
180 f_decoded_value = fMultiply(f_decoded_value, f_range);
181 f_decoded_value = fAdd(f_decoded_value, f_min);
182
183 return f_decoded_value;
184}
185
186
187static fInt fDecodeLogisticFuse(uint32_t fuse_value, fInt f_average, fInt f_range, uint32_t bitlength)
188{
189 fInt f_fuse_value = Convert_ULONG_ToFraction(fuse_value);
190 fInt f_bit_max_value = Convert_ULONG_ToFraction((uPow(2, bitlength)) - 1);
191
192 fInt f_CONSTANT_NEG13 = ConvertToFraction(-13);
193 fInt f_CONSTANT1 = ConvertToFraction(1);
194
195 fInt f_decoded_value;
196
197 f_decoded_value = fSubtract(fDivide(f_bit_max_value, f_fuse_value), f_CONSTANT1);
198 f_decoded_value = fNaturalLog(f_decoded_value);
199 f_decoded_value = fMultiply(f_decoded_value, fDivide(f_range, f_CONSTANT_NEG13));
200 f_decoded_value = fAdd(f_decoded_value, f_average);
201
202 return f_decoded_value;
203}
204
205static fInt fDecodeLeakageID (uint32_t leakageID_fuse, fInt ln_max_div_min, fInt f_min, uint32_t bitlength)
206{
207 fInt fLeakage;
208 fInt f_bit_max_value = Convert_ULONG_ToFraction((uPow(2, bitlength)) - 1);
209
210 fLeakage = fMultiply(ln_max_div_min, Convert_ULONG_ToFraction(leakageID_fuse));
211 fLeakage = fDivide(fLeakage, f_bit_max_value);
212 fLeakage = fExponential(fLeakage);
213 fLeakage = fMultiply(fLeakage, f_min);
214
215 return fLeakage;
216}
217
218static fInt ConvertToFraction(int X) /*Add all range checking here. Is it possible to make fInt a private declaration? */
219{
220 fInt temp;
221
222 if (X <= PPMAX(1 << (16 - 1)) - 1)
223 temp.full = (X << SHIFT_AMOUNT16);
224 else
225 temp.full = 0;
226
227 return temp;
228}
229
230static fInt fNegate(fInt X)
231{
232 fInt CONSTANT_NEGONE = ConvertToFraction(-1);
233 return (fMultiply(X, CONSTANT_NEGONE));
234}
235
236static fInt Convert_ULONG_ToFraction(uint32_t X)
237{
238 fInt temp;
239
240 if (X <= PPMAX(1 << (16 - 1)) - 1)
241 temp.full = (X << SHIFT_AMOUNT16);
242 else
243 temp.full = 0;
244
245 return temp;
246}
247
248static fInt GetScaledFraction(int X, int factor)
249{
250 int times_shifted, factor_shifted;
251 bool_Bool bNEGATED;
252 fInt fValue;
253
254 times_shifted = 0;
255 factor_shifted = 0;
256 bNEGATED = false0;
257
258 if (X < 0) {
259 X = -1*X;
260 bNEGATED = true1;
261 }
262
263 if (factor < 0) {
264 factor = -1*factor;
265 bNEGATED = !bNEGATED; /*If bNEGATED = true due to X < 0, this will cover the case of negative cancelling negative */
266 }
267
268 if ((X > PPMAX(1 << (16 - 1)) - 1) || factor > PPMAX(1 << (16 - 1)) - 1) {
269 if ((X/factor) <= PPMAX(1 << (16 - 1)) - 1) {
270 while (X > PPMAX(1 << (16 - 1)) - 1) {
271 X = X >> 1;
272 times_shifted++;
273 }
274
275 while (factor > PPMAX(1 << (16 - 1)) - 1) {
276 factor = factor >> 1;
277 factor_shifted++;
278 }
279 } else {
280 fValue.full = 0;
281 return fValue;
282 }
283 }
284
285 if (factor == 1)
286 return ConvertToFraction(X);
287
288 fValue = fDivide(ConvertToFraction(X * uPow(-1, bNEGATED)), ConvertToFraction(factor));
289
290 fValue.full = fValue.full << times_shifted;
291 fValue.full = fValue.full >> factor_shifted;
292
293 return fValue;
294}
295
296/* Addition using two fInts */
297static fInt fAdd (fInt X, fInt Y)
298{
299 fInt Sum;
300
301 Sum.full = X.full + Y.full;
302
303 return Sum;
304}
305
306/* Addition using two fInts */
307static fInt fSubtract (fInt X, fInt Y)
308{
309 fInt Difference;
310
311 Difference.full = X.full - Y.full;
312
313 return Difference;
314}
315
316static bool_Bool Equal(fInt A, fInt B)
317{
318 if (A.full == B.full)
319 return true1;
320 else
321 return false0;
322}
323
324static bool_Bool GreaterThan(fInt A, fInt B)
325{
326 if (A.full > B.full)
327 return true1;
328 else
329 return false0;
330}
331
332static fInt fMultiply (fInt X, fInt Y) /* Uses 64-bit integers (int64_t) */
333{
334 fInt Product;
335 int64_t tempProduct;
336 bool_Bool X_LessThanOne, Y_LessThanOne;
337
338 X_LessThanOne = (X.partial.real == 0 && X.partial.decimal != 0 && X.full >= 0);
339 Y_LessThanOne = (Y.partial.real == 0 && Y.partial.decimal != 0 && Y.full >= 0);
Value stored to 'Y_LessThanOne' is never read
340
341 /*The following is for a very specific common case: Non-zero number with ONLY fractional portion*/
342 /* TEMPORARILY DISABLED - CAN BE USED TO IMPROVE PRECISION
343
344 if (X_LessThanOne && Y_LessThanOne) {
345 Product.full = X.full * Y.full;
346 return Product
347 }*/
348
349 tempProduct = ((int64_t)X.full) * ((int64_t)Y.full); /*Q(16,16)*Q(16,16) = Q(32, 32) - Might become a negative number! */
350 tempProduct = tempProduct >> 16; /*Remove lagging 16 bits - Will lose some precision from decimal; */
351 Product.full = (int)tempProduct; /*The int64_t will lose the leading 16 bits that were part of the integer portion */
352
353 return Product;
354}
355
356static fInt fDivide (fInt X, fInt Y)
357{
358 fInt fZERO, fQuotient;
359 int64_t longlongX, longlongY;
360
361 fZERO = ConvertToFraction(0);
362
363 if (Equal(Y, fZERO))
364 return fZERO;
365
366 longlongX = (int64_t)X.full;
367 longlongY = (int64_t)Y.full;
368
369 longlongX = longlongX << 16; /*Q(16,16) -> Q(32,32) */
370
371 div64_s64(longlongX, longlongY); /*Q(32,32) divided by Q(16,16) = Q(16,16) Back to original format */
372
373 fQuotient.full = (int)longlongX;
374 return fQuotient;
375}
376
377static int ConvertBackToInteger (fInt A) /*THIS is the function that will be used to check with the Golden settings table*/
378{
379 fInt fullNumber, scaledDecimal, scaledReal;
380
381 scaledReal.full = GetReal(A) * uPow(10, PRECISION5-1); /* DOUBLE CHECK THISSSS!!! */
382
383 scaledDecimal.full = uGetScaledDecimal(A);
384
385 fullNumber = fAdd(scaledDecimal,scaledReal);
386
387 return fullNumber.full;
388}
389
390static fInt fGetSquare(fInt A)
391{
392 return fMultiply(A,A);
393}
394
395/* x_new = x_old - (x_old^2 - C) / (2 * x_old) */
396static fInt fSqrt(fInt num)
397{
398 fInt F_divide_Fprime, Fprime;
399 fInt test;
400 fInt twoShifted;
401 int seed, counter, error;
402 fInt x_new, x_old, C, y;
403
404 fInt fZERO = ConvertToFraction(0);
405
406 /* (0 > num) is the same as (num < 0), i.e., num is negative */
407
408 if (GreaterThan(fZERO, num) || Equal(fZERO, num))
409 return fZERO;
410
411 C = num;
412
413 if (num.partial.real > 3000)
414 seed = 60;
415 else if (num.partial.real > 1000)
416 seed = 30;
417 else if (num.partial.real > 100)
418 seed = 10;
419 else
420 seed = 2;
421
422 counter = 0;
423
424 if (Equal(num, fZERO)) /*Square Root of Zero is zero */
425 return fZERO;
426
427 twoShifted = ConvertToFraction(2);
428 x_new = ConvertToFraction(seed);
429
430 do {
431 counter++;
432
433 x_old.full = x_new.full;
434
435 test = fGetSquare(x_old); /*1.75*1.75 is reverting back to 1 when shifted down */
436 y = fSubtract(test, C); /*y = f(x) = x^2 - C; */
437
438 Fprime = fMultiply(twoShifted, x_old);
439 F_divide_Fprime = fDivide(y, Fprime);
440
441 x_new = fSubtract(x_old, F_divide_Fprime);
442
443 error = ConvertBackToInteger(x_new) - ConvertBackToInteger(x_old);
444
445 if (counter > 20) /*20 is already way too many iterations. If we dont have an answer by then, we never will*/
446 return x_new;
447
448 } while (uAbs(error) > 0);
449
450 return (x_new);
451}
452
453static void SolveQuadracticEqn(fInt A, fInt B, fInt C, fInt Roots[])
454{
455 fInt *pRoots = &Roots[0];
456 fInt temp, root_first, root_second;
457 fInt f_CONSTANT10, f_CONSTANT100;
458
459 f_CONSTANT100 = ConvertToFraction(100);
460 f_CONSTANT10 = ConvertToFraction(10);
461
462 while(GreaterThan(A, f_CONSTANT100) || GreaterThan(B, f_CONSTANT100) || GreaterThan(C, f_CONSTANT100)) {
463 A = fDivide(A, f_CONSTANT10);
464 B = fDivide(B, f_CONSTANT10);
465 C = fDivide(C, f_CONSTANT10);
466 }
467
468 temp = fMultiply(ConvertToFraction(4), A); /* root = 4*A */
469 temp = fMultiply(temp, C); /* root = 4*A*C */
470 temp = fSubtract(fGetSquare(B), temp); /* root = b^2 - 4AC */
471 temp = fSqrt(temp); /*root = Sqrt (b^2 - 4AC); */
472
473 root_first = fSubtract(fNegate(B), temp); /* b - Sqrt(b^2 - 4AC) */
474 root_second = fAdd(fNegate(B), temp); /* b + Sqrt(b^2 - 4AC) */
475
476 root_first = fDivide(root_first, ConvertToFraction(2)); /* [b +- Sqrt(b^2 - 4AC)]/[2] */
477 root_first = fDivide(root_first, A); /*[b +- Sqrt(b^2 - 4AC)]/[2*A] */
478
479 root_second = fDivide(root_second, ConvertToFraction(2)); /* [b +- Sqrt(b^2 - 4AC)]/[2] */
480 root_second = fDivide(root_second, A); /*[b +- Sqrt(b^2 - 4AC)]/[2*A] */
481
482 *(pRoots + 0) = root_first;
483 *(pRoots + 1) = root_second;
484}
485
486/* -----------------------------------------------------------------------------
487 * SUPPORT FUNCTIONS
488 * -----------------------------------------------------------------------------
489 */
490
491/* Conversion Functions */
492static int GetReal (fInt A)
493{
494 return (A.full >> SHIFT_AMOUNT16);
495}
496
497static fInt Divide (int X, int Y)
498{
499 fInt A, B, Quotient;
500
501 A.full = X << SHIFT_AMOUNT16;
502 B.full = Y << SHIFT_AMOUNT16;
503
504 Quotient = fDivide(A, B);
505
506 return Quotient;
507}
508
509static int uGetScaledDecimal (fInt A) /*Converts the fractional portion to whole integers - Costly function */
510{
511 int dec[PRECISION5];
512 int i, scaledDecimal = 0, tmp = A.partial.decimal;
513
514 for (i = 0; i < PRECISION5; i++) {
515 dec[i] = tmp / (1 << SHIFT_AMOUNT16);
516 tmp = tmp - ((1 << SHIFT_AMOUNT16)*dec[i]);
517 tmp *= 10;
518 scaledDecimal = scaledDecimal + dec[i]*uPow(10, PRECISION5 - 1 -i);
519 }
520
521 return scaledDecimal;
522}
523
524static int uPow(int base, int power)
525{
526 if (power == 0)
527 return 1;
528 else
529 return (base)*uPow(base, power - 1);
530}
531
532static int uAbs(int X)
533{
534 if (X < 0)
535 return (X * -1);
536 else
537 return X;
538}
539
540static fInt fRoundUpByStepSize(fInt A, fInt fStepSize, bool_Bool error_term)
541{
542 fInt solution;
543
544 solution = fDivide(A, fStepSize);
545 solution.partial.decimal = 0; /*All fractional digits changes to 0 */
546
547 if (error_term)
548 solution.partial.real += 1; /*Error term of 1 added */
549
550 solution = fMultiply(solution, fStepSize);
551 solution = fAdd(solution, fStepSize);
552
553 return solution;
554}
555