4 // Copyright (c) 2000 - 2003, Intel Corporation
5 // All rights reserved.
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37 // http://www.intel.com/software/products/opensource/libraries/num.htm.
39 //********************************************************************
41 //********************************************************************
42 // 02/02/00 Initial version
43 // 04/04/00 Unwind support added
44 // 08/15/00 Bundle added after call to __libm_error_support to properly
45 // set [the previously overwritten] GR_Parameter_RESULT.
46 // 02/10/03 Reordered header: .section, .global, .proc, .align
48 //********************************************************************
50 // Function: Combined sqrt(x), where
52 // sqrt(x) = |x, for double precision x values
54 //********************************************************************
56 // Accuracy: Correctly Rounded
58 //********************************************************************
62 // Floating-Point Registers: f8 (Input and Return Value)
65 // General Purpose Registers:
67 // r37-r40 (Used to pass arguments to error handling routine)
69 // Predicate Registers: p6, p7, p8
71 //*********************************************************************
73 // IEEE Special Conditions:
75 // All faults and exceptions should be raised correctly.
79 // sqrt(negative) = QNaN and error handling is called
81 //*********************************************************************
85 // Modified Newton-Raphson Algorithm
87 //*********************************************************************
95 GR_Parameter_RESULT = r39
99 GLOBAL_IEEE754_ENTRY(sqrt)
101 alloc r32= ar.pfs,0,5,4,0
105 // BEGIN DOUBLE PRECISION MINIMUM LATENCY SQUARE ROOT ALGORITHM
107 // exponent of +1/2 in r2
121 // y0 = 1/sqrt(a) in f7
122 fclass.m.unc p7,p8 = f8,0x3A
131 movl r3 = 0x40fc0000;;
135 // h = +1/2 * y0 in f6
136 (p6) fma.s1 f6=f9,f7,f0
142 (p6) fma.s1 f7=f8,f7,f0
151 movl r2 = 0x41670000;;
155 // e = 1/2 - g * h in f9
156 (p6) fnma.s1 f9=f7,f6,f9
161 movl r3 = 0x408c0000;;
165 // S = 3/2 + 5/2 * e in f10
166 (p6) fma.s1 f10=f11,f9,f10
172 (p6) fma.s1 f11=f9,f9,f0
177 // t = 63/8 + 231/16 * e in f12
178 (p6) fma.s1 f12=f13,f9,f12
183 // S1 = e + e2 * S in f10
184 (p6) fma.s1 f10=f11,f10,f9
189 // e4 = e2 * e2 in f11
190 (p6) fma.s1 f11=f11,f11,f0
195 // t1 = 35/8 + e * t in f9
196 (p6) fma.s1 f9=f9,f12,f14
201 // G = g + S1 * g in f12
202 (p6) fma.s1 f12=f10,f7,f7
208 (p6) fma.s1 f7=f7,f11,f0
213 // u = S1 + e4 * t1 in f10
214 (p6) fma.s1 f10=f11,f9,f10
219 // g1 = G + t1 * E in f7
220 (p6) fma.d.s1 f7=f9,f7,f12
225 // h1 = h + u * h in f6
226 (p6) fma.s1 f6=f10,f6,f6
231 // d = a - g1 * g1 in f9
232 (p6) fnma.s1 f9=f7,f7,f8
237 // g2 = g1 + d * h1 in f7
238 (p6) fma.d.s0 f8=f9,f6,f7
239 (p6) br.ret.sptk b0 ;;
245 (p8) br.ret.sptk b0 ;;
250 (p7) br.cond.sptk __libm_error_region ;;
252 // END DOUBLE PRECISION MINIMUM LATENCY SQUARE ROOT ALGORITHM
253 GLOBAL_IEEE754_END(sqrt)
254 libm_alias_double_other (__sqrt, sqrt)
255 libm_alias_double_narrow (__sqrt, sqrt)
257 // Stack operations when calling error support.
258 // (1) (2) (3) (call) (4)
259 // sp -> + psp -> + psp -> + sp -> +
261 // | | <- GR_Y R3 ->| <- GR_RESULT | -> f8
263 // | <-GR_Y Y2->| Y2 ->| <- GR_Y |
265 // | | <- GR_X X1 ->| |
267 // sp-64 -> + sp -> + sp -> + +
268 // save ar.pfs save b0 restore gp
269 // save gp restore ar.pfs
272 LOCAL_LIBM_ENTRY(__libm_error_region)
275 // This branch includes all those special values that are not negative,
276 // with the result equal to frcpa(x)
280 // We are distinguishing between over(under)flow and letting
281 // __libm_error_support set ERANGE or do anything else needed.
285 add GR_Parameter_Y=-32,sp // Parameter 2 value
287 .save ar.pfs,GR_SAVE_PFS
288 mov GR_SAVE_PFS=ar.pfs // Save ar.pfs
292 add sp=-64,sp // Create new stack
294 mov GR_SAVE_GP=gp // Save gp
300 stfd [GR_Parameter_Y] = f0,16 // STORE Parameter 2 on stack
301 add GR_Parameter_X = 16,sp // Parameter 1 address
303 mov GR_SAVE_B0=b0 // Save b0
309 stfd [GR_Parameter_X] = f15 // STORE Parameter 1 on stack
310 add GR_Parameter_RESULT = 0,GR_Parameter_Y // Parameter 3 address
314 stfd [GR_Parameter_Y] = f8 // STORE Parameter 3 on stack
315 add GR_Parameter_Y = -16,GR_Parameter_Y
316 br.call.sptk b0=__libm_error_support# // Call error handling function
321 add GR_Parameter_RESULT = 48,sp
326 ldfd f8 = [GR_Parameter_RESULT] // Get return result off stack
328 add sp = 64,sp // Restore stack pointer
329 mov b0 = GR_SAVE_B0 // Restore return address
332 mov gp = GR_SAVE_GP // Restore gp
333 mov ar.pfs = GR_SAVE_PFS // Restore ar.pfs
334 br.ret.sptk b0 // Return
337 LOCAL_LIBM_END(__libm_error_region)
342 .type __libm_error_support#,@function
343 .global __libm_error_support#