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| 1 ;; Copyright 2010 the V8 project authors. All rights reserved. | |
| 2 ;; Redistribution and use in source and binary forms, with or without | |
| 3 ;; modification, are permitted provided that the following conditions are | |
| 4 ;; met: | |
| 5 ;; | |
| 6 ;; * Redistributions of source code must retain the above copyright | |
| 7 ;; notice, this list of conditions and the following disclaimer. | |
| 8 ;; * Redistributions in binary form must reproduce the above | |
| 9 ;; copyright notice, this list of conditions and the following | |
| 10 ;; disclaimer in the documentation and/or other materials provided | |
| 11 ;; with the distribution. | |
| 12 ;; * Neither the name of Google Inc. nor the names of its | |
| 13 ;; contributors may be used to endorse or promote products derived | |
| 14 ;; from this software without specific prior written permission. | |
| 15 ;; | |
| 16 ;; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 17 ;; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 18 ;; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 19 ;; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 20 ;; OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 21 ;; SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 22 ;; LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 23 ;; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 24 ;; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 25 ;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 26 ;; OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 27 | |
| 28 ;; This is a Scheme script for the Bigloo compiler. Bigloo must be compiled with | |
| 29 ;; support for bignums. The compilation of the script can be done as follows: | |
| 30 ;; bigloo -static-bigloo -o generate-ten-powers generate-ten-powers.scm | |
| 31 ;; | |
| 32 ;; Generate approximations of 10^k. | |
| 33 | |
| 34 (module gen-ten-powers | |
| 35 (static (class Cached-Fast | |
| 36 v::bignum | |
| 37 e::bint | |
| 38 exact?::bool)) | |
| 39 (main my-main)) | |
| 40 | |
| 41 | |
| 42 ;;----------------bignum shifts ----------------------------------------------- | |
| 43 (define (bit-lshbx::bignum x::bignum by::bint) | |
| 44 (if (<fx by 0) | |
| 45 #z0 | |
| 46 (*bx x (exptbx #z2 (fixnum->bignum by))))) | |
| 47 | |
| 48 (define (bit-rshbx::bignum x::bignum by::bint) | |
| 49 (if (<fx by 0) | |
| 50 #z0 | |
| 51 (/bx x (exptbx #z2 (fixnum->bignum by))))) | |
| 52 | |
| 53 ;;----------------the actual power generation ------------------------------- | |
| 54 | |
| 55 ;; e should be an indication. it might be too small. | |
| 56 (define (round-n-cut n e nb-bits) | |
| 57 (define max-container (- (bit-lshbx #z1 nb-bits) 1)) | |
| 58 (define (round n) | |
| 59 (case *round* | |
| 60 ((down) n) | |
| 61 ((up) | |
| 62 (+bx n | |
| 63 ;; with the -1 it will only round up if the cut off part is | |
| 64 ;; non-zero | |
| 65 (-bx (bit-lshbx #z1 | |
| 66 (-fx (+fx e nb-bits) 1)) | |
| 67 #z1))) | |
| 68 ((round) | |
| 69 (+bx n | |
| 70 (bit-lshbx #z1 | |
| 71 (-fx (+fx e nb-bits) 2)))))) | |
| 72 (let* ((shift (-fx (+fx e nb-bits) 1)) | |
| 73 (cut (bit-rshbx (round n) shift)) | |
| 74 (exact? (=bx n (bit-lshbx cut shift)))) | |
| 75 (if (<=bx cut max-container) | |
| 76 (values cut e exact?) | |
| 77 (round-n-cut n (+fx e 1) nb-bits)))) | |
| 78 | |
| 79 (define (rounded-/bx x y) | |
| 80 (case *round* | |
| 81 ((down) (/bx x y)) | |
| 82 ((up) (+bx (/bx x y) #z1)) | |
| 83 ((round) (let ((tmp (/bx (*bx #z2 x) y))) | |
| 84 (if (zerobx? (remainderbx tmp #z2)) | |
| 85 (/bx tmp #z2) | |
| 86 (+bx (/bx tmp #z2) #z1)))))) | |
| 87 | |
| 88 (define (generate-powers from to mantissa-size) | |
| 89 (let* ((nb-bits mantissa-size) | |
| 90 (offset (- from)) | |
| 91 (nb-elements (+ (- from) to 1)) | |
| 92 (vec (make-vector nb-elements)) | |
| 93 (max-container (- (bit-lshbx #z1 nb-bits) 1))) | |
| 94 ;; the negative ones. 10^-1, 10^-2, etc. | |
| 95 ;; We already know, that we can't be exact, so exact? will always be #f. | |
| 96 ;; Basically we will have a ten^i that we will *10 at each iteration. We | |
| 97 ;; want to create the matissa of 1/ten^i. However the mantissa must be | |
| 98 ;; normalized (start with a 1). -> we have to shift the number. | |
| 99 ;; We shift by multiplying with two^e. -> We encode two^e*(1/ten^i) == | |
| 100 ;; two^e/ten^i. | |
| 101 (let loop ((i 1) | |
| 102 (ten^i #z10) | |
| 103 (two^e #z1) | |
| 104 (e 0)) | |
| 105 (unless (< (- i) from) | |
| 106 (if (>bx (/bx (*bx #z2 two^e) ten^i) max-container) | |
| 107 ;; another shift would make the number too big. We are | |
| 108 ;; hence normalized now. | |
| 109 (begin | |
| 110 (vector-set! vec (-fx offset i) | |
| 111 (instantiate::Cached-Fast | |
| 112 (v (rounded-/bx two^e ten^i)) | |
| 113 (e (negfx e)) | |
| 114 (exact? #f))) | |
| 115 (loop (+fx i 1) (*bx ten^i #z10) two^e e)) | |
| 116 (loop i ten^i (bit-lshbx two^e 1) (+fx e 1))))) | |
| 117 ;; the positive ones 10^0, 10^1, etc. | |
| 118 ;; start with 1.0. mantissa: 10...0 (1 followed by nb-bits-1 bits) | |
| 119 ;; -> e = -(nb-bits-1) | |
| 120 ;; exact? is true when the container can still hold the complete 10^i | |
| 121 (let loop ((i 0) | |
| 122 (n (bit-lshbx #z1 (-fx nb-bits 1))) | |
| 123 (e (-fx 1 nb-bits))) | |
| 124 (when (<= i to) | |
| 125 (receive (cut e exact?) | |
| 126 (round-n-cut n e nb-bits) | |
| 127 (vector-set! vec (+fx i offset) | |
| 128 (instantiate::Cached-Fast | |
| 129 (v cut) | |
| 130 (e e) | |
| 131 (exact? exact?))) | |
| 132 (loop (+fx i 1) (*bx n #z10) e)))) | |
| 133 vec)) | |
| 134 | |
| 135 (define (print-c powers from to struct-type | |
| 136 cache-name max-distance-name offset-name macro64) | |
| 137 (define (display-power power k) | |
| 138 (with-access::Cached-Fast power (v e exact?) | |
| 139 (let ((tmp-p (open-output-string))) | |
| 140 ;; really hackish way of getting the digits | |
| 141 (display (format "~x" v) tmp-p) | |
| 142 (let ((str (close-output-port tmp-p))) | |
| 143 (printf " {~a(0x~a, ~a), ~a, ~a},\n" | |
| 144 macro64 | |
| 145 (substring str 0 8) | |
| 146 (substring str 8 16) | |
| 147 e | |
| 148 k))))) | |
| 149 (define (print-powers-reduced n) | |
| 150 (print "static const " struct-type " " cache-name | |
| 151 "(" n ")" | |
| 152 "[] = {") | |
| 153 (let loop ((i 0) | |
| 154 (nb-elements 0) | |
| 155 (last-e 0) | |
| 156 (max-distance 0)) | |
| 157 (cond | |
| 158 ((>= i (vector-length powers)) | |
| 159 (print " };") | |
| 160 (print "static const int " max-distance-name "(" n ") = " | |
| 161 max-distance ";") | |
| 162 (print "// nb elements (" n "): " nb-elements)) | |
| 163 (else | |
| 164 (let* ((power (vector-ref powers i)) | |
| 165 (e (Cached-Fast-e power))) | |
| 166 (display-power power (+ i from)) | |
| 167 (loop (+ i n) | |
| 168 (+ nb-elements 1) | |
| 169 e | |
| 170 (cond | |
| 171 ((=fx i 0) max-distance) | |
| 172 ((> (- e last-e) max-distance) (- e last-e)) | |
| 173 (else max-distance)))))))) | |
| 174 (print "// Copyright 2010 the V8 project authors. All rights reserved.") | |
| 175 (print "// ------------ GENERATED FILE ----------------") | |
| 176 (print "// command used:") | |
| 177 (print "// " | |
| 178 (apply string-append (map (lambda (str) | |
| 179 (string-append " " str)) | |
| 180 *main-args*)) | |
| 181 " // NOLINT") | |
| 182 (print) | |
| 183 (print | |
| 184 "// This file is intended to be included inside another .h or .cc files\n" | |
| 185 "// with the following defines set:\n" | |
| 186 "// GRISU_CACHE_STRUCT: should expand to the name of a struct that will\n" | |
| 187 "// hold the cached powers of ten. Each entry will hold a 64-bit\n" | |
| 188 "// significand, a 16-bit signed binary exponent, and a 16-bit\n" | |
| 189 "// signed decimal exponent. Each entry will be constructed as follows:\n" | |
| 190 "// { significand, binary_exponent, decimal_exponent }.\n" | |
| 191 "// GRISU_CACHE_NAME(i): generates the name for the different caches.\n" | |
| 192 "// The parameter i will be a number in the range 1-20. A cache will\n" | |
| 193 "// hold every i'th element of a full cache. GRISU_CACHE_NAME(1) will\n" | |
| 194 "// thus hold all elements. The higher i the fewer elements it has.\n" | |
| 195 "// Ideally the user should only reference one cache and let the\n" | |
| 196 "// compiler remove the unused ones.\n" | |
| 197 "// GRISU_CACHE_MAX_DISTANCE(i): generates the name for the maximum\n" | |
| 198 "// binary exponent distance between all elements of a given cache.\n" | |
| 199 "// GRISU_CACHE_OFFSET: is used as variable name for the decimal\n" | |
| 200 "// exponent offset. It is equal to -cache[0].decimal_exponent.\n" | |
| 201 "// GRISU_UINT64_C: used to construct 64-bit values in a platform\n" | |
| 202 "// independent way. In order to encode 0x123456789ABCDEF0 the macro\n" | |
| 203 "// will be invoked as follows: GRISU_UINT64_C(0x12345678,9ABCDEF0).\n") | |
| 204 (print) | |
| 205 (print-powers-reduced 1) | |
| 206 (print-powers-reduced 2) | |
| 207 (print-powers-reduced 3) | |
| 208 (print-powers-reduced 4) | |
| 209 (print-powers-reduced 5) | |
| 210 (print-powers-reduced 6) | |
| 211 (print-powers-reduced 7) | |
| 212 (print-powers-reduced 8) | |
| 213 (print-powers-reduced 9) | |
| 214 (print-powers-reduced 10) | |
| 215 (print-powers-reduced 11) | |
| 216 (print-powers-reduced 12) | |
| 217 (print-powers-reduced 13) | |
| 218 (print-powers-reduced 14) | |
| 219 (print-powers-reduced 15) | |
| 220 (print-powers-reduced 16) | |
| 221 (print-powers-reduced 17) | |
| 222 (print-powers-reduced 18) | |
| 223 (print-powers-reduced 19) | |
| 224 (print-powers-reduced 20) | |
| 225 (print "static const int GRISU_CACHE_OFFSET = " (- from) ";")) | |
| 226 | |
| 227 ;;----------------main -------------------------------------------------------- | |
| 228 (define *main-args* #f) | |
| 229 (define *mantissa-size* #f) | |
| 230 (define *dest* #f) | |
| 231 (define *round* #f) | |
| 232 (define *from* #f) | |
| 233 (define *to* #f) | |
| 234 | |
| 235 (define (my-main args) | |
| 236 (set! *main-args* args) | |
| 237 (args-parse (cdr args) | |
| 238 (section "Help") | |
| 239 (("?") (args-parse-usage #f)) | |
| 240 ((("-h" "--help") (help "?, -h, --help" "This help message")) | |
| 241 (args-parse-usage #f)) | |
| 242 (section "Misc") | |
| 243 (("-o" ?file (help "The output file")) | |
| 244 (set! *dest* file)) | |
| 245 (("--mantissa-size" ?size (help "Container-size in bits")) | |
| 246 (set! *mantissa-size* (string->number size))) | |
| 247 (("--round" ?direction (help "Round bignums (down, round or up)")) | |
| 248 (set! *round* (string->symbol direction))) | |
| 249 (("--from" ?from (help "start at 10^from")) | |
| 250 (set! *from* (string->number from))) | |
| 251 (("--to" ?to (help "go up to 10^to")) | |
| 252 (set! *to* (string->number to))) | |
| 253 (else | |
| 254 (print "Illegal argument `" else "'. Usage:") | |
| 255 (args-parse-usage #f))) | |
| 256 (when (not *from*) | |
| 257 (error "generate-ten-powers" | |
| 258 "Missing from" | |
| 259 #f)) | |
| 260 (when (not *to*) | |
| 261 (error "generate-ten-powers" | |
| 262 "Missing to" | |
| 263 #f)) | |
| 264 (when (not *mantissa-size*) | |
| 265 (error "generate-ten-powers" | |
| 266 "Missing mantissa size" | |
| 267 #f)) | |
| 268 (when (not (memv *round* '(up down round))) | |
| 269 (error "generate-ten-powers" | |
| 270 "Missing round-method" | |
| 271 *round*)) | |
| 272 | |
| 273 (let ((dividers (generate-powers *from* *to* *mantissa-size*)) | |
| 274 (p (if (not *dest*) | |
| 275 (current-output-port) | |
| 276 (open-output-file *dest*)))) | |
| 277 (unwind-protect | |
| 278 (with-output-to-port p | |
| 279 (lambda () | |
| 280 (print-c dividers *from* *to* | |
| 281 "GRISU_CACHE_STRUCT" "GRISU_CACHE_NAME" | |
| 282 "GRISU_CACHE_MAX_DISTANCE" "GRISU_CACHE_OFFSET" | |
| 283 "GRISU_UINT64_C" | |
| 284 ))) | |
| 285 (if *dest* | |
| 286 (close-output-port p))))) | |
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