diff options
Diffstat (limited to 'payloads/libpayload/libc')
| -rw-r--r-- | payloads/libpayload/libc/64bit_div.c | 141 | ||||
| -rw-r--r-- | payloads/libpayload/libc/Makefile.inc | 4 |
2 files changed, 145 insertions, 0 deletions
diff --git a/payloads/libpayload/libc/64bit_div.c b/payloads/libpayload/libc/64bit_div.c new file mode 100644 index 0000000000..615a2d8fdd --- /dev/null +++ b/payloads/libpayload/libc/64bit_div.c @@ -0,0 +1,141 @@ +/* + * This file is part of the libpayload project. + * + * Copyright 2014 Google Inc. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. The name of the author may not be used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <libpayload-config.h> +#include <stdlib.h> + +#ifndef CONFIG_LP_LITTLE_ENDIAN +#error this code is for little endian only +#endif + +union overlay64 { + uint64_t longw; + struct { + uint32_t lower; + uint32_t higher; + } words; +}; + + +uint64_t __ashldi3(uint64_t num, unsigned shift) +{ + union overlay64 output; + + output.longw = num; + if (shift >= 32) { + output.words.higher = output.words.lower << (shift - 32); + output.words.lower = 0; + } else { + if (!shift) + return num; + output.words.higher = (output.words.higher << shift) | + (output.words.lower >> (32 - shift)); + output.words.lower = output.words.lower << shift; + } + return output.longw; +} + +uint64_t __lshrdi3(uint64_t num, unsigned shift) +{ + union overlay64 output; + + output.longw = num; + if (shift >= 32) { + output.words.lower = output.words.higher >> (shift - 32); + output.words.higher = 0; + } else { + if (!shift) + return num; + output.words.lower = output.words.lower >> shift | + (output.words.higher << (32 - shift)); + output.words.higher = output.words.higher >> shift; + } + return output.longw; +} + +#define MAX_32BIT_UINT ((((uint64_t)1) << 32) - 1) + +static uint64_t _64bit_divide(uint64_t dividend, + uint64_t divider, uint64_t *rem_p) +{ + uint64_t result = 0; + + /* + * If divider is zero - let the rest of the system care about the + * exception. + */ + if (!divider) + return 1/(uint32_t)divider; + + /* As an optimization, let's not use 64 bit division unless we must. */ + if (dividend <= MAX_32BIT_UINT) { + if (divider > MAX_32BIT_UINT) { + result = 0; + if (rem_p) + *rem_p = divider; + } else { + result = (uint32_t) dividend / (uint32_t) divider; + if (rem_p) + *rem_p = (uint32_t) dividend % + (uint32_t) divider; + } + return result; + } + + while (divider <= dividend) { + uint64_t locald = divider; + uint64_t limit = __lshrdi3(dividend, 1); + int shifts = 0; + + while (locald <= limit) { + shifts++; + locald = locald + locald; + } + result |= __ashldi3(1, shifts); + dividend -= locald; + } + + if (rem_p) + *rem_p = dividend; + + return result; +} + +uint64_t __udivdi3(uint64_t num, uint64_t den) +{ + return _64bit_divide(num, den, NULL); +} + +uint64_t __umoddi3(uint64_t num, uint64_t den) +{ + uint64_t v = 0; + + _64bit_divide(num, den, &v); + return v; +} diff --git a/payloads/libpayload/libc/Makefile.inc b/payloads/libpayload/libc/Makefile.inc index bd2a6f7595..b4f75a6cb5 100644 --- a/payloads/libpayload/libc/Makefile.inc +++ b/payloads/libpayload/libc/Makefile.inc @@ -41,3 +41,7 @@ libc-$(CONFIG_LP_LIBC) += coreboot.c # should be moved to coreboot directory libc-$(CONFIG_LP_LAR) += lar.c + +ifeq ($(CONFIG_LP_ARCH_MIPS),y) +libc-$(CONFIG_LP_LIBC) += 64bit_div.c +endif |