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1/****************************************************************************
2
3 exp.s
4
5 by Stephen Canon
6
7 Copyright © 2007, Apple Inc. All Rights Reserved.
8
9 Implementation of the C99 exp function for the MacOS X i386 and x86_64 ABIs.
10
11****************************************************************************/
12#include <machine/asm.h>
13#include "abi.h"
14
15
16
17
18/****************************************************************************
19
20 Tables and Constants
21
22****************************************************************************/
23.const
24.align 4
25
26
27 // Coefficients for the 4th order minimax polynomial
28 // approximation of exp2( ) on the interval [-0x1p-27, 0x1p-7]
29 // constructed by A. Sazegari
30 .quad 0x0000000000000000 // padding
31 .quad 0x3f55e52272e0eaec // c4
32 .quad 0x3f83b2a8abda3d8f // c3
33 .quad 0x3fac6b08d78310b8 // c2
34 .quad 0x3fcebfbdff82bda7 // c1
35 .quad 0x3fe62e42fefa39ef // c0
36
37 // table of values of x for which exp2(x) is very precise in
38 // double precision constructed by J. Kidder.
39 // x exp2(x)
40exp2table: .quad 0xbfe000000005f3f1, 0x3fe6a09e667c50df // x = -0x1.000000005f3f1p-1, exp2(x) = 0x1.6a09e667c50dfp-1 to 76 bits
41 .quad 0xbfdf800000504e67, 0x3fe6c01274f81141 // x = -0x1.f800000504e67p-2, exp2(x) = 0x1.6c01274f81141p-1 to 75 bits
42 .quad 0xbfdf000000413114, 0x3fe6dfb23c54f3bf // x = -0x1.f000000413114p-2, exp2(x) = 0x1.6dfb23c54f3bfp-1 to 75 bits
43 .quad 0xbfde800000026750, 0x3fe6ff7df950fb41 // x = -0x1.e800000026750p-2, exp2(x) = 0x1.6ff7df950fb41p-1 to 75 bits
44 .quad 0xbfde00000001f188, 0x3fe71f75e8ebe2db // x = -0x1.e00000001f188p-2, exp2(x) = 0x1.71f75e8ebe2dbp-1 to 75 bits
45 .quad 0xbfdd800000060771, 0x3fe73f9a48a3fcd4 // x = -0x1.d800000060771p-2, exp2(x) = 0x1.73f9a48a3fcd4p-1 to 75 bits
46 .quad 0xbfdd000000027151, 0x3fe75feb5641c97b // x = -0x1.d000000027151p-2, exp2(x) = 0x1.75feb5641c97bp-1 to 75 bits
47 .quad 0xbfdc800000133b3c, 0x3fe780694fd97820 // x = -0x1.c800000133b3cp-2, exp2(x) = 0x1.780694fd97820p-1 to 77 bits
48 .quad 0xbfdc000000006742, 0x3fe7a11473eae71a // x = -0x1.c000000006742p-2, exp2(x) = 0x1.7a11473eae71ap-1 to 76 bits
49 .quad 0xbfdb8000000026c4, 0x3fe7c1ed0130b739 // x = -0x1.b8000000026c4p-2, exp2(x) = 0x1.7c1ed0130b739p-1 to 75 bits
50 .quad 0xbfdb00000010b0f8, 0x3fe7e2f336cafcf6 // x = -0x1.b00000010b0f8p-2, exp2(x) = 0x1.7e2f336cafcf6p-1 to 75 bits
51 .quad 0xbfda800000006fca, 0x3fe80427543dfcfe // x = -0x1.a800000006fcap-2, exp2(x) = 0x1.80427543dfcfep-1 to 75 bits
52 .quad 0xbfda0000000a60b7, 0x3fe82589994a174b // x = -0x1.a0000000a60b7p-2, exp2(x) = 0x1.82589994a174bp-1 to 75 bits
53 .quad 0xbfd98000000f3180, 0x3fe8471a461fc8fa // x = -0x1.98000000f3180p-2, exp2(x) = 0x1.8471a461fc8fap-1 to 82 bits
54 .quad 0xbfd9000000065897, 0x3fe868d99b42e570 // x = -0x1.9000000065897p-2, exp2(x) = 0x1.868d99b42e570p-1 to 76 bits
55 .quad 0xbfd8800000057289, 0x3fe88ac7d988f3ee // x = -0x1.8800000057289p-2, exp2(x) = 0x1.88ac7d988f3eep-1 to 76 bits
56 .quad 0xbfd800000005c28b, 0x3fe8ace5422916cb // x = -0x1.800000005c28bp-2, exp2(x) = 0x1.8ace5422916cbp-1 to 75 bits
57 .quad 0xbfd780000060838c, 0x3fe8cf32169b55bb // x = -0x1.780000060838cp-2, exp2(x) = 0x1.8cf32169b55bbp-1 to 75 bits
58 .quad 0xbfd7000000160f6a, 0x3fe8f1ae990f8189 // x = -0x1.7000000160f6ap-2, exp2(x) = 0x1.8f1ae990f8189p-1 to 75 bits
59 .quad 0xbfd6800000015814, 0x3fe9145b0b91a250 // x = -0x1.6800000015814p-2, exp2(x) = 0x1.9145b0b91a250p-1 to 79 bits
60 .quad 0xbfd600000005b1dc, 0x3fe93737b0cc37c2 // x = -0x1.600000005b1dcp-2, exp2(x) = 0x1.93737b0cc37c2p-1 to 75 bits
61 .quad 0xbfd58000000ced09, 0x3fe95a44cbc4c577 // x = -0x1.58000000ced09p-2, exp2(x) = 0x1.95a44cbc4c577p-1 to 75 bits
62 .quad 0xbfd500000004055e, 0x3fe97d829fdd3222 // x = -0x1.500000004055ep-2, exp2(x) = 0x1.97d829fdd3222p-1 to 76 bits
63 .quad 0xbfd4800000044514, 0x3fe9a0f170c8d852 // x = -0x1.4800000044514p-2, exp2(x) = 0x1.9a0f170c8d852p-1 to 75 bits
64 .quad 0xbfd400000062eb27, 0x3fe9c49182885576 // x = -0x1.400000062eb27p-2, exp2(x) = 0x1.9c49182885576p-1 to 76 bits
65 .quad 0xbfd380000025f5a3, 0x3fe9e86319d87c72 // x = -0x1.380000025f5a3p-2, exp2(x) = 0x1.9e86319d87c72p-1 to 75 bits
66 .quad 0xbfd300000026d9fb, 0x3fea0c667b52ef7a // x = -0x1.300000026d9fbp-2, exp2(x) = 0x1.a0c667b52ef7ap-1 to 75 bits
67 .quad 0xbfd28000000ef1d6, 0x3fea309bec45f003 // x = -0x1.28000000ef1d6p-2, exp2(x) = 0x1.a309bec45f003p-1 to 75 bits
68 .quad 0xbfd200000028a35e, 0x3fea5503b2328e73 // x = -0x1.200000028a35ep-2, exp2(x) = 0x1.a5503b2328e73p-1 to 75 bits
69 .quad 0xbfd18000003892f0, 0x3fea799e13207a90 // x = -0x1.18000003892f0p-2, exp2(x) = 0x1.a799e13207a90p-1 to 77 bits
70 .quad 0xbfd100000036ebd4, 0x3fea9e6b556a2865 // x = -0x1.100000036ebd4p-2, exp2(x) = 0x1.a9e6b556a2865p-1 to 75 bits
71 .quad 0xbfd08000001df4d6, 0x3feac36bbfcb4499 // x = -0x1.08000001df4d6p-2, exp2(x) = 0x1.ac36bbfcb4499p-1 to 75 bits
72 .quad 0xbfd00000007109bc, 0x3feae89f9939e248 // x = -0x1.00000007109bcp-2, exp2(x) = 0x1.ae89f9939e248p-1 to 76 bits
73 .quad 0xbfcf0000000d0ce0, 0x3feb0e07298bccef // x = -0x1.f0000000d0ce0p-3, exp2(x) = 0x1.b0e07298bccefp-1 to 76 bits
74 .quad 0xbfce000000038571, 0x3feb33a2b84e9132 // x = -0x1.e000000038571p-3, exp2(x) = 0x1.b33a2b84e9132p-1 to 75 bits
75 .quad 0xbfcd0000003291c8, 0x3feb59728ddddbeb // x = -0x1.d0000003291c8p-3, exp2(x) = 0x1.b59728ddddbebp-1 to 77 bits
76 .quad 0xbfcc00000009a474, 0x3feb7f76f2f9eeb5 // x = -0x1.c00000009a474p-3, exp2(x) = 0x1.b7f76f2f9eeb5p-1 to 77 bits
77 .quad 0xbfcb000000041435, 0x3feba5b030a069f4 // x = -0x1.b000000041435p-3, exp2(x) = 0x1.ba5b030a069f4p-1 to 77 bits
78 .quad 0xbfca0000001c5bde, 0x3febcc1e90477d01 // x = -0x1.a0000001c5bdep-3, exp2(x) = 0x1.bcc1e90477d01p-1 to 76 bits
79 .quad 0xbfc90000000fd3f7, 0x3febf2c25bd4b8c9 // x = -0x1.90000000fd3f7p-3, exp2(x) = 0x1.bf2c25bd4b8c9p-1 to 76 bits
80 .quad 0xbfc800000042ee2b, 0x3fec199bdd7b2358 // x = -0x1.800000042ee2bp-3, exp2(x) = 0x1.c199bdd7b2358p-1 to 76 bits
81 .quad 0xbfc700000012ef60, 0x3fec40ab5ffceadc // x = -0x1.700000012ef60p-3, exp2(x) = 0x1.c40ab5ffceadcp-1 to 78 bits
82 .quad 0xbfc600000017f9f5, 0x3fec67f12e542120 // x = -0x1.600000017f9f5p-3, exp2(x) = 0x1.c67f12e542120p-1 to 75 bits
83 .quad 0xbfc50000001c6b03, 0x3fec8f6d9402828e // x = -0x1.50000001c6b03p-3, exp2(x) = 0x1.c8f6d9402828ep-1 to 75 bits
84 .quad 0xbfc40000004dc028, 0x3fecb720dce37952 // x = -0x1.40000004dc028p-3, exp2(x) = 0x1.cb720dce37952p-1 to 75 bits
85 .quad 0xbfc300000002c957, 0x3fecdf0b555d5473 // x = -0x1.300000002c957p-3, exp2(x) = 0x1.cdf0b555d5473p-1 to 80 bits
86 .quad 0xbfc20000000307a2, 0x3fed072d4a070f8f // x = -0x1.20000000307a2p-3, exp2(x) = 0x1.d072d4a070f8fp-1 to 77 bits
87 .quad 0xbfc100000008225f, 0x3fed2f87080c40d5 // x = -0x1.100000008225fp-3, exp2(x) = 0x1.d2f87080c40d5p-1 to 78 bits
88 .quad 0xbfc00000000d35cc, 0x3fed5818dcf98b25 // x = -0x1.00000000d35ccp-3, exp2(x) = 0x1.d5818dcf98b25p-1 to 75 bits
89 .quad 0xbfbe00000000a23c, 0x3fed80e316c976a2 // x = -0x1.e00000000a23cp-4, exp2(x) = 0x1.d80e316c976a2p-1 to 75 bits
90 .quad 0xbfbc0000001a43df, 0x3feda9e603d9167a // x = -0x1.c0000001a43dfp-4, exp2(x) = 0x1.da9e603d9167ap-1 to 75 bits
91 .quad 0xbfba0000000a59b6, 0x3fedd321f300de67 // x = -0x1.a0000000a59b6p-4, exp2(x) = 0x1.dd321f300de67p-1 to 78 bits
92 .quad 0xbfb800000004084f, 0x3fedfc97337b478e // x = -0x1.800000004084fp-4, exp2(x) = 0x1.dfc97337b478ep-1 to 75 bits
93 .quad 0xbfb60000000cc2e4, 0x3fee264614f49679 // x = -0x1.60000000cc2e4p-4, exp2(x) = 0x1.e264614f49679p-1 to 75 bits
94 .quad 0xbfb40000002a7000, 0x3fee502ee787c449 // x = -0x1.40000002a7000p-4, exp2(x) = 0x1.e502ee787c449p-1 to 75 bits
95 .quad 0xbfb20000001b557e, 0x3fee7a51fbc50b11 // x = -0x1.20000001b557ep-4, exp2(x) = 0x1.e7a51fbc50b11p-1 to 79 bits
96 .quad 0xbfb0000000067db9, 0x3feea4afa2a406fa // x = -0x1.0000000067db9p-4, exp2(x) = 0x1.ea4afa2a406fap-1 to 75 bits
97 .quad 0xbfac0000004cac7c, 0x3feecf482d8b353b // x = -0x1.c0000004cac7cp-5, exp2(x) = 0x1.ecf482d8b353bp-1 to 79 bits
98 .quad 0xbfa80000002255b2, 0x3feefa1bee5fe98b // x = -0x1.80000002255b2p-5, exp2(x) = 0x1.efa1bee5fe98bp-1 to 75 bits
99 .quad 0xbfa40000000fbb0b, 0x3fef252b376b10cb // x = -0x1.40000000fbb0bp-5, exp2(x) = 0x1.f252b376b10cbp-1 to 75 bits
100 .quad 0xbfa000000013426b, 0x3fef50765b6d743c // x = -0x1.000000013426bp-5, exp2(x) = 0x1.f50765b6d743cp-1 to 75 bits
101 .quad 0xbf980000001b1b4b, 0x3fef7bfdad9c2a30 // x = -0x1.80000001b1b4bp-6, exp2(x) = 0x1.f7bfdad9c2a30p-1 to 75 bits
102 .quad 0xbf90000000108597, 0x3fefa7c1819e3637 // x = -0x1.0000000108597p-6, exp2(x) = 0x1.fa7c1819e3637p-1 to 75 bits
103 .quad 0xbf800000001446bb, 0x3fefd3c22b8f3a07 // x = -0x1.00000001446bbp-7, exp2(x) = 0x1.fd3c22b8f3a07p-1 to 78 bits
104 .quad 0x0000000000000000, 0x3ff0000000000000 // x = 0x0.0000000000000p+0, exp2(x) = 0x1.0000000000000p+0 exactly
105 .quad 0x3f80000000046787, 0x3ff0163da9fb3959 // x = 0x1.0000000046787p-7, exp2(x) = 0x1.0163da9fb3959p+0 to 75 bits
106 .quad 0x3f90000000413bdf, 0x3ff02c9a3e783737 // x = 0x1.0000000413bdfp-6, exp2(x) = 0x1.02c9a3e783737p+0 to 75 bits
107 .quad 0x3f9800000009e3ad, 0x3ff04315e86e9b63 // x = 0x1.800000009e3adp-6, exp2(x) = 0x1.04315e86e9b63p+0 to 75 bits
108 .quad 0x3fa00000000c4c0e, 0x3ff059b0d315cb23 // x = 0x1.00000000c4c0ep-5, exp2(x) = 0x1.059b0d315cb23p+0 to 77 bits
109 .quad 0x3fa40000001dce0d, 0x3ff0706b29dea0ad // x = 0x1.40000001dce0dp-5, exp2(x) = 0x1.0706b29dea0adp+0 to 76 bits
110 .quad 0x3fa80000002def51, 0x3ff087451876a2e9 // x = 0x1.80000002def51p-5, exp2(x) = 0x1.087451876a2e9p+0 to 79 bits
111 .quad 0x3fac000000110f6a, 0x3ff09e3ecac755c5 // x = 0x1.c000000110f6ap-5, exp2(x) = 0x1.09e3ecac755c5p+0 to 75 bits
112 .quad 0x3fb0000000042de0, 0x3ff0b5586cf9b976 // x = 0x1.0000000042de0p-4, exp2(x) = 0x1.0b5586cf9b976p+0 to 75 bits
113 .quad 0x3fb20000000af8a9, 0x3ff0cc922b72c7b8 // x = 0x1.20000000af8a9p-4, exp2(x) = 0x1.0cc922b72c7b8p+0 to 75 bits
114 .quad 0x3fb40000000120ca, 0x3ff0e3ec32d3ded7 // x = 0x1.40000000120cap-4, exp2(x) = 0x1.0e3ec32d3ded7p+0 to 77 bits
115 .quad 0x3fb600000008f69e, 0x3ff0fb66afff3c9d // x = 0x1.600000008f69ep-4, exp2(x) = 0x1.0fb66afff3c9dp+0 to 75 bits
116 .quad 0x3fb8000000305124, 0x3ff11301d0149725 // x = 0x1.8000000305124p-4, exp2(x) = 0x1.11301d0149725p+0 to 76 bits
117 .quad 0x3fba0000000021c9, 0x3ff12abdc06c335e // x = 0x1.a0000000021c9p-4, exp2(x) = 0x1.12abdc06c335ep+0 to 75 bits
118 .quad 0x3fbc0000000b765e, 0x3ff1429aaea9b702 // x = 0x1.c0000000b765ep-4, exp2(x) = 0x1.1429aaea9b702p+0 to 75 bits
119 .quad 0x3fbe0000000561d9, 0x3ff15a98c8a5cf0f // x = 0x1.e0000000561d9p-4, exp2(x) = 0x1.15a98c8a5cf0fp+0 to 75 bits
120 .quad 0x3fc00000000d9993, 0x3ff172b83c7e9a70 // x = 0x1.00000000d9993p-3, exp2(x) = 0x1.172b83c7e9a70p+0 to 76 bits
121 .quad 0x3fc10000001aa7db, 0x3ff18af9388f162b // x = 0x1.10000001aa7dbp-3, exp2(x) = 0x1.18af9388f162bp+0 to 76 bits
122 .quad 0x3fc2000000023143, 0x3ff1a35beb700111 // x = 0x1.2000000023143p-3, exp2(x) = 0x1.1a35beb700111p+0 to 76 bits
123 .quad 0x3fc300000035902b, 0x3ff1bbe0840981a5 // x = 0x1.300000035902bp-3, exp2(x) = 0x1.1bbe0840981a5p+0 to 78 bits
124 .quad 0x3fc40000000c261e, 0x3ff1d4873169e5f6 // x = 0x1.40000000c261ep-3, exp2(x) = 0x1.1d4873169e5f6p+0 to 76 bits
125 .quad 0x3fc50000000f8bff, 0x3ff1ed5022fe5b7c // x = 0x1.50000000f8bffp-3, exp2(x) = 0x1.1ed5022fe5b7cp+0 to 75 bits
126 .quad 0x3fc600000019e18b, 0x3ff2063b88651387 // x = 0x1.600000019e18bp-3, exp2(x) = 0x1.2063b88651387p+0 to 78 bits
127 .quad 0x3fc700000010f9d2, 0x3ff21f49917f8711 // x = 0x1.700000010f9d2p-3, exp2(x) = 0x1.21f49917f8711p+0 to 78 bits
128 .quad 0x3fc800000021f3d9, 0x3ff2387a6e78bbd5 // x = 0x1.800000021f3d9p-3, exp2(x) = 0x1.2387a6e78bbd5p+0 to 76 bits
129 .quad 0x3fc900000007aca6, 0x3ff251ce4fb36926 // x = 0x1.900000007aca6p-3, exp2(x) = 0x1.251ce4fb36926p+0 to 77 bits
130 .quad 0x3fca0000000834d3, 0x3ff26b4565e34e68 // x = 0x1.a0000000834d3p-3, exp2(x) = 0x1.26b4565e34e68p+0 to 76 bits
131 .quad 0x3fcb0000000f383c, 0x3ff284dfe1f6ea3c // x = 0x1.b0000000f383cp-3, exp2(x) = 0x1.284dfe1f6ea3cp+0 to 75 bits
132 .quad 0x3fcc000000295470, 0x3ff29e9df52409b2 // x = 0x1.c000000295470p-3, exp2(x) = 0x1.29e9df52409b2p+0 to 75 bits
133 .quad 0x3fcd000000aa2014, 0x3ff2b87fd0ec18b9 // x = 0x1.d000000aa2014p-3, exp2(x) = 0x1.2b87fd0ec18b9p+0 to 75 bits
134 .quad 0x3fce00000089ee06, 0x3ff2d285a6f21217 // x = 0x1.e00000089ee06p-3, exp2(x) = 0x1.2d285a6f21217p+0 to 77 bits
135 .quad 0x3fcf00000011e56f, 0x3ff2ecafa94004d8 // x = 0x1.f00000011e56fp-3, exp2(x) = 0x1.2ecafa94004d8p+0 to 76 bits
136 .quad 0x3fd00000002450b9, 0x3ff306fe0a3932e5 // x = 0x1.00000002450b9p-2, exp2(x) = 0x1.306fe0a3932e5p+0 to 78 bits
137 .quad 0x3fd0800000018109, 0x3ff32170fc4d27f8 // x = 0x1.0800000018109p-2, exp2(x) = 0x1.32170fc4d27f8p+0 to 75 bits
138 .quad 0x3fd10000000f3232, 0x3ff33c08b2674165 // x = 0x1.10000000f3232p-2, exp2(x) = 0x1.33c08b2674165p+0 to 75 bits
139 .quad 0x3fd18000000237f0, 0x3ff356c55f9316e5 // x = 0x1.18000000237f0p-2, exp2(x) = 0x1.356c55f9316e5p+0 to 76 bits
140 .quad 0x3fd20000000199c8, 0x3ff371a7373b0016 // x = 0x1.20000000199c8p-2, exp2(x) = 0x1.371a7373b0016p+0 to 75 bits
141 .quad 0x3fd28000000b48f9, 0x3ff38cae6d083c14 // x = 0x1.28000000b48f9p-2, exp2(x) = 0x1.38cae6d083c14p+0 to 75 bits
142 .quad 0x3fd30000004c6957, 0x3ff3a7db34f5e42c // x = 0x1.30000004c6957p-2, exp2(x) = 0x1.3a7db34f5e42cp+0 to 77 bits
143 .quad 0x3fd38000004e208e, 0x3ff3c32dc32461b8 // x = 0x1.38000004e208ep-2, exp2(x) = 0x1.3c32dc32461b8p+0 to 75 bits
144 .quad 0x3fd4000000013df2, 0x3ff3dea64c12788e // x = 0x1.4000000013df2p-2, exp2(x) = 0x1.3dea64c12788ep+0 to 75 bits
145 .quad 0x3fd480000015af05, 0x3ff3fa4504b13129 // x = 0x1.480000015af05p-2, exp2(x) = 0x1.3fa4504b13129p+0 to 78 bits
146 .quad 0x3fd500000009a838, 0x3ff4160a21f947f9 // x = 0x1.500000009a838p-2, exp2(x) = 0x1.4160a21f947f9p+0 to 75 bits
147 .quad 0x3fd5800000234f8c, 0x3ff431f5d95861bd // x = 0x1.5800000234f8cp-2, exp2(x) = 0x1.431f5d95861bdp+0 to 77 bits
148 .quad 0x3fd600000003a7aa, 0x3ff44e08606256f0 // x = 0x1.600000003a7aap-2, exp2(x) = 0x1.44e08606256f0p+0 to 78 bits
149 .quad 0x3fd68000000e661d, 0x3ff46a41ed202f5b // x = 0x1.68000000e661dp-2, exp2(x) = 0x1.46a41ed202f5bp+0 to 75 bits
150 .quad 0x3fd700000047e5a0, 0x3ff486a2b5d13877 // x = 0x1.700000047e5a0p-2, exp2(x) = 0x1.486a2b5d13877p+0 to 75 bits
151 .quad 0x3fd780000013fc02, 0x3ff4a32af0dc4b5b // x = 0x1.780000013fc02p-2, exp2(x) = 0x1.4a32af0dc4b5bp+0 to 75 bits
152 .quad 0x3fd800000018514b, 0x3ff4bfdad53ba122 // x = 0x1.800000018514bp-2, exp2(x) = 0x1.4bfdad53ba122p+0 to 75 bits
153 .quad 0x3fd88000004b65dc, 0x3ff4dcb29a0ee638 // x = 0x1.88000004b65dcp-2, exp2(x) = 0x1.4dcb29a0ee638p+0 to 76 bits
154 .quad 0x3fd90000002a7909, 0x3ff4f9b276a6d2b4 // x = 0x1.90000002a7909p-2, exp2(x) = 0x1.4f9b276a6d2b4p+0 to 76 bits
155 .quad 0x3fd98000000e9ddf, 0x3ff516daa2d2bcec // x = 0x1.98000000e9ddfp-2, exp2(x) = 0x1.516daa2d2bcecp+0 to 77 bits
156 .quad 0x3fda0000001165b7, 0x3ff5342b56a14e49 // x = 0x1.a0000001165b7p-2, exp2(x) = 0x1.5342b56a14e49p+0 to 76 bits
157 .quad 0x3fda800000347522, 0x3ff551a4ca69aec0 // x = 0x1.a800000347522p-2, exp2(x) = 0x1.551a4ca69aec0p+0 to 76 bits
158 .quad 0x3fdb000000163445, 0x3ff56f4736ba4f70 // x = 0x1.b000000163445p-2, exp2(x) = 0x1.56f4736ba4f70p+0 to 75 bits
159 .quad 0x3fdb800000173fe4, 0x3ff58d12d49d3534 // x = 0x1.b800000173fe4p-2, exp2(x) = 0x1.58d12d49d3534p+0 to 75 bits
160 .quad 0x3fdc0000000bbaca, 0x3ff5ab07dd4b14d7 // x = 0x1.c0000000bbacap-2, exp2(x) = 0x1.5ab07dd4b14d7p+0 to 76 bits
161 .quad 0x3fdc80000016a2c1, 0x3ff5c9268a5e9dfb // x = 0x1.c80000016a2c1p-2, exp2(x) = 0x1.5c9268a5e9dfbp+0 to 75 bits
162 .quad 0x3fdd0000004564c2, 0x3ff5e76f15bd979e // x = 0x1.d0000004564c2p-2, exp2(x) = 0x1.5e76f15bd979ep+0 to 75 bits
163 .quad 0x3fdd8000001d2bb6, 0x3ff605e1b97dd138 // x = 0x1.d8000001d2bb6p-2, exp2(x) = 0x1.605e1b97dd138p+0 to 75 bits
164 .quad 0x3fde000000122703, 0x3ff6247eb03eafef // x = 0x1.e000000122703p-2, exp2(x) = 0x1.6247eb03eafefp+0 to 76 bits
165 .quad 0x3fde8000001fd876, 0x3ff6434634d470cf // x = 0x1.e8000001fd876p-2, exp2(x) = 0x1.6434634d470cfp+0 to 76 bits
166 .quad 0x3fdf0000004a6dab, 0x3ff6623882672d39 // x = 0x1.f0000004a6dabp-2, exp2(x) = 0x1.6623882672d39p+0 to 76 bits
167 .quad 0x3fdf80000033c91f, 0x3ff68155d45948c1 // x = 0x1.f80000033c91fp-2, exp2(x) = 0x1.68155d45948c1p+0 to 75 bits
168 .quad 0x3fe000000006d6f2, 0x3ff6a09e668295fd // x = 0x1.000000006d6f2p-1, exp2(x) = 0x1.6a09e668295fdp+0 to 76 bits
169 // Other useful constants
170
171small_poly: .quad 0x3ff0000000000000
172 .quad 0x3fdffffffffffe1f
173 .quad 0x3fc55555555553f0
174 .quad 0x3fa55555ca407ccb
175 .quad 0x3f8111116e99ac77
176
177.literal8
178.align 3
179lge_p7: .quad 0x40671547652b82fe
180lge: .quad 0x3ff71547652b82fe
181lge_hi: .quad 0x3ff7154760000000
182lge_lo: .quad 0x3e54ae0bf85ddf44
183split_mask: .quad 0xfffffffff8000000
184tiny_val: .quad 0x0010000000000001
185huge_val: .quad 0x7fefffffffffffff
186neg_inf: .quad 0xfff0000000000000
187
188#if defined( __x86_64__ )
189abs_mask: .quad 0x7fffffffffffffff // Constants needed on x86_64
190small_cut: .quad 0x3f662e42fefa39ef // because there are no 8-byte
191large_cut: .quad 0x011ff4e8de8082e3 // immediates
192tiny_cut: .quad 0xfd19d1bd0105c611
193huge_cut: .quad 0x01211d42457337d4
194#endif
195
196overflow: .quad 0x40862e42fefa39ef // Overflow boundary
197underflow: .quad 0xc086232bdd7abcd2 // Underflow boundary
198
199/****************************************************************************
200
201 PIC code
202
203****************************************************************************/
204.text
205#if defined(__x86_64__)
206 #define REL_ADDR(_a) (_a)(%rip)
207#else
208 #define REL_ADDR(_a) (_a)-0b(%ecx)
209#endif
210
211
212
213
214/****************************************************************************
215
216 Entry point for exp( )
217
218****************************************************************************/
219ENTRY(exp)
220
221#if defined(__x86_64__)
222 movd %xmm0, %rax
223 movd %xmm0, %rdx
224 and REL_ADDR(abs_mask), %rax // |x|
225 sar $63, %rdx // (x < 0) ? -1 : 0
226 sub REL_ADDR(small_cut), %rax
227 add $64, %rdx // bias = (x < 0) ? 63 : 64
228 cmp REL_ADDR(large_cut), %rax // if (log(2) |x| < 0x1p-8 or log(2) |x| > 1022 or isnan(x))
229 ja 2f // goto 2
230#else
231 movl 4+FRAME_SIZE(STACKP), %eax
232 movl 4+FRAME_SIZE(STACKP), %edx
233 movsd FRAME_SIZE(STACKP), %xmm0
234 call 0f
2350: pop %ecx
236 and $0x7fffffff, %eax // hi word of |x|
237 sar $31, %edx // (x < 0) ? -1 : 0
238 sub $0x3f662e43, %eax
239 add $64, %edx // bias = (x < 0) ? 63 : 64
240 cmp $0x011ff4e7, %eax // if (log(2) |x| < 0x1p-8ish or log(2) |x| > 1022ish or isnan(x))
241 ja 2f // goto 2
242#endif
243
244 // Code path for 0x1.0p-8 < log(2) |x| < 1022
2451:
246 // Value Notes
247 movapd %xmm0, %xmm1 // --------------------------------------------------------------
248 mulsd REL_ADDR(lge_p7), %xmm0 // 0x1.0p7 phi 53 bits
249 cvttsd2si %xmm0, AX_P // trunc(0x1.0p7 phi) integer, relative error < 53 bits
250 add DX_P, AX_P // trunc(0x1.0p7 phi) + bias
251 mov AX_P, DX_P
252 sar $7, AX_P // n = round(phi) not quite round-to-nearest, but
253 // more than good enough.
254 and $0x7f, DX_P // a = 7 bits of phi - n -1/2 <= a/128 < 1/2
255 sal $4, DX_P // a * sizeof(table entry)
256
257 movapd %xmm1, %xmm2
258 mulsd REL_ADDR(lge), %xmm1 // phi 53 bits
259 cvtsi2sd AX_P, %xmm0 // (double)n
260
261 movapd %xmm1, %xmm7
262 subsd %xmm0, %xmm1 // phi - n always exact
263
264
265 movapd %xmm2, %xmm4
266 movsd REL_ADDR(split_mask), %xmm3
267 mulsd REL_ADDR(lge_lo), %xmm4 // x * lge_lo rounded to 53 bits
268 movsd REL_ADDR(lge_hi), %xmm5 // lg(e) lg(e) rounded to 26 bits
269 // lge_hi + lge_lo = lg(e) to 80 bits
270
271 lea REL_ADDR(exp2table), CX_P
272 subsd (DX_P, CX_P, 1), %xmm1 // ((phi - n) - fhi) always exact on the given range
273 // approximation to flo
274 movsd -40(CX_P), %xmm6 // c4
275 mulsd %xmm1, %xmm6 // c4 flu "flu" = approximate flo
276 addsd -32(CX_P), %xmm6 // c4 flu + c3 .
277 mulsd %xmm1, %xmm6 // (c4 flu + c3) flu .
278 addsd -24(CX_P), %xmm6 // (c4 flu + c3) flu + c2 ,
279
280 andpd %xmm2, %xmm3 // xhi x truncated to 26 bits
281 subsd %xmm3, %xmm2 // xlo xhi + xlo = x exactly (53 bits)
282 mulsd %xmm5, %xmm3 // xhi * lge_hi exact
283 mulsd %xmm5, %xmm2 // xlo * lge_hi exact
284 subsd %xmm7, %xmm3 // xhi*lge_hi - phi
285 addsd %xmm3, %xmm2 // (xhi*lge_hi - phi) + xlo*lge_hi
286 addsd %xmm4, %xmm2 // plo phi + plo is 79 bits accurate
287
288 addsd %xmm1, %xmm2 // ((phi - n) - fhi) + plo actual flo
289 movapd %xmm2, %xmm3
290 mulsd %xmm2, %xmm6 // ((c4 flu + c3) flu + c2) flo
291 mulsd %xmm3, %xmm3 // flo * flo
292 addsd -16(CX_P), %xmm6 // ((c4 flu + c3) flu + c2) flo + c1
293 mulsd -8(CX_P), %xmm2 // c0 flo
294 mulsd %xmm6, %xmm3 // (((c4 flu + c3) flu + c2) flo + c1) flo flo
295 addsd %xmm3, %xmm2 // flo p(flo, flu) polynomial approximation to exp2(flo) - 1
296 // accurate to 60 bits of exp2(fhi)
297
298 movd AX_P, %xmm4
299 psllq $52, %xmm4 // n shifted into the exponent bits of a double
300
301 movsd 8(DX_P, CX_P, 1), %xmm0 // exp2(fhi) accurate to 74 bits
302
303 mulsd %xmm0, %xmm2
304 addsd %xmm2, %xmm0 // exp2(fhi + flo) accurate to .51625 ulp
305
306 paddd %xmm4, %xmm0 // exp2(n + fhi + flo) = exp(x) multiply by 2**n is done by adding n to
307 // the exponent of exp2(fhi + flo).
308
309#if defined(__i386__)
310 movsd %xmm0, FRAME_SIZE(STACKP)
311 fldl FRAME_SIZE(STACKP)
312#endif
313 ret
314
3152: jg 4f // if (log(2) |x| > 1022 or isnan(x))
316 // goto 4
317
318 // Code path for log(2) |x| < 0x1.0p-8
319#if defined( __x86_64__ )
320 cmp REL_ADDR(tiny_cut), %rax // if (|x| < 0x1p-55)
321#else
322 cmp $0xfd19d1bd, %eax // if (|x| < 0x1p-55ish)
323#endif
324 jbe 3f // goto 3
325
326 // Minimax polynomial approximation to exp( ) on [ -lg(e) 0x1.0p-8, lg(e) 0x1.0p-8 ]
327 //
328 // The approximation has the form 1.0 + x p(x), where p(x) has at most 1 ulp error.
329 // Because |x| is < 0x1.0p-8, then, the error of the final result is bounded by .508125 ulp
330 lea REL_ADDR(small_poly), DX_P
331 movapd %xmm0, %xmm1
332 mulsd 32(DX_P), %xmm0
333 addsd 24(DX_P), %xmm0
334 mulsd %xmm1, %xmm0
335 addsd 16(DX_P), %xmm0
336 mulsd %xmm1, %xmm0
337 addsd 8(DX_P), %xmm0
338 mulsd %xmm1, %xmm0
339 addsd (DX_P), %xmm0
340 mulsd %xmm1, %xmm0
341 addsd (DX_P), %xmm0
342
343#if defined(__i386__)
344 movsd %xmm0, FRAME_SIZE(STACKP)
345 fldl FRAME_SIZE(STACKP)
346#endif
347 ret
348
3493: // exp(x) = 1.0 + x for tiny x
350 addsd REL_ADDR(small_poly), %xmm0
351
352#if defined(__i386__)
353 movsd %xmm0, FRAME_SIZE(STACKP)
354 fldl FRAME_SIZE(STACKP)
355#endif
356 ret
357
3584:
359#if defined( __x86_64__ )
360 cmp REL_ADDR(huge_cut), %rax // if (the result will be NaN, inf, or zero)
361#else
362 cmp $0x01211d43, %eax // if (the result will be NaN, inf, or zero)
363#endif
364 jg 5f // goto 5
365
366 // Here we handle cases very close to the over/underflow boundary.
367 // Compare x with zero to determine whether we're in the overflow or underflow case
368 xorpd %xmm1, %xmm1
369 comisd %xmm1, %xmm0 // if (x > 0.0)
370 jnc 6f // goto 6
371
372#if defined( __i386__ )
373 // One extra test is needed in 32-bit mode to determine exactly which side of the underflow
374 // boundary we are on.
375
376 movsd REL_ADDR(underflow), %xmm1
377 comisd %xmm1, %xmm0 // if (x >= underflow boundary)
378 jnc 1b // go back into the mainline
379 // otherwise, fall through into underflow code
380#endif
381
382 // (near) overflows have been correctly handled, we handle gradual underflows here
383
384 // This code is largely copied from the mainline branch. To make identifying and explaining
385 // the changes easier, all comments have been removed, except where the algorithm differs
386 // from the mainline. For details on the uncommented lines, consult above.
387 movapd %xmm0, %xmm1
388 mulsd REL_ADDR(lge_p7), %xmm0
389 cvttsd2si %xmm0, AX_P
390 add DX_P, AX_P
391 mov AX_P, DX_P
392 sar $7, AX_P
393 and $0x7f, DX_P
394 sal $4, DX_P
395
396 movsd REL_ADDR(tiny_val), %xmm6 // load 0x1p-1022
397 mulsd %xmm6, %xmm6 // multiply to force underflow flag.
398
399 movapd %xmm1, %xmm2
400 mulsd REL_ADDR(lge), %xmm1
401 cvtsi2sd AX_P, %xmm0
402
403 movapd %xmm1, %xmm7
404 subsd %xmm0, %xmm1
405
406 movapd %xmm2, %xmm4
407 movsd REL_ADDR(split_mask), %xmm3
408 mulsd REL_ADDR(lge_lo), %xmm4
409 movsd REL_ADDR(lge_hi), %xmm5
410 movsd REL_ADDR(small_poly), %xmm0 // load 1.0
411
412 lea REL_ADDR(exp2table), CX_P
413 subsd (DX_P, CX_P, 1), %xmm1
414
415 movsd -40(CX_P), %xmm6
416 mulsd %xmm1, %xmm6
417 addsd -32(CX_P), %xmm6
418 mulsd %xmm1, %xmm6
419 addsd -24(CX_P), %xmm6
420
421 andpd %xmm2, %xmm3
422 subsd %xmm3, %xmm2
423 mulsd %xmm5, %xmm3
424 mulsd %xmm5, %xmm2
425 subsd %xmm7, %xmm3
426 addsd %xmm3, %xmm2
427 addsd %xmm4, %xmm2
428
429 addsd %xmm1, %xmm2
430 movapd %xmm2, %xmm3
431 mulsd %xmm2, %xmm6
432 mulsd %xmm3, %xmm3
433 addsd -16(CX_P), %xmm6
434 mulsd -8(CX_P), %xmm2
435 mulsd %xmm6, %xmm3
436 addsd %xmm3, %xmm2
437
438 add $1022, AX_P // add 1022 to n before we place it into the exponent bits
439 movd AX_P, %xmm4
440 psllq $52, %xmm4
441
442 movsd 8(DX_P, CX_P, 1), %xmm1
443 paddd %xmm4, %xmm1 // hi = exp2(1022 + n + fhi)
444
445 mulsd %xmm1, %xmm2
446
447 movapd %xmm1, %xmm3
448 addsd %xmm0, %xmm1 // 1.0 + hi rounded to 53 bits
449 movapd %xmm1, %xmm4
450 subsd %xmm0, %xmm1 // (1.0 + hi) - 1.0 exact
451 subsd %xmm1, %xmm3 // hi - (1.0 + hi) - 1.0 rounding error from 1.0 + hi
452 addsd %xmm3, %xmm2 // exp2(flo) + rounding error from above
453
454 addsd %xmm2, %xmm4 // (1.0 + hi) + exp2(flo) + round error
455 // 1.0 forces the round to happen
456 // in the correct place for the
457 // denormal value
458
459 xorpd %xmm4, %xmm0 // set correct exponent for denormal
460
461#if defined(__i386__)
462 movsd %xmm0, FRAME_SIZE(STACKP)
463 fldl FRAME_SIZE(STACKP)
464#endif
465 ret
466
4675:
468 ucomisd %xmm0, %xmm0 // if isnan(x)
469 jp 8f // goto 8
470
471 xorpd %xmm1, %xmm1
472 comisd %xmm1, %xmm0 // if (x > 0.0)
473 jnc 7f // goto 7
474
475 movsd REL_ADDR(neg_inf), %xmm1
476 cmpneqsd %xmm0, %xmm1 // (x != -inf) ? -1ULL : 0
477 movsd REL_ADDR(tiny_val), %xmm0
478 andpd %xmm0, %xmm1 // (x != -inf) ? 0x1p-1022 : 0
479 mulsd %xmm1, %xmm0 // (x != -inf) ? 0 w/ underflow, inexact : exact 0
480
481#if defined(__i386__)
482 movsd %xmm0, FRAME_SIZE(STACKP)
483 fldl FRAME_SIZE(STACKP)
484#endif
485 ret
486
4876: // Here we need to do the floating-point compare to determine exactly which side
488 // of the overflow boundary we are on.
489 movsd REL_ADDR(overflow), %xmm1
490 comisd %xmm0, %xmm1 // if (x <= overflow boundary)
491 jnc 1b // go back into the mainline
492 // otherwise, fall through into overflow code
493
4947: // Handle positive overflows with multiplication by huge val
495 // Sets overflow, inexact for finite values, gives exact
496 // infinity for +inf
497 mulsd REL_ADDR(huge_val), %xmm0
498
499#if defined(__i386__)
500 movsd %xmm0, FRAME_SIZE(STACKP)
501 fldl FRAME_SIZE(STACKP)
502#endif
503 ret
504
5058: // Handle NaN by addition to quiet.
506 addsd %xmm0, %xmm0
507
508#if defined(__i386__)
509 movsd %xmm0, FRAME_SIZE(STACKP)
510 fldl FRAME_SIZE(STACKP)
511#endif
512 ret