diff options
Diffstat (limited to 'arch/parisc/include')
| -rw-r--r-- | arch/parisc/include/asm/hash.h | 146 | ||||
| -rw-r--r-- | arch/parisc/include/asm/mc146818rtc.h | 9 | ||||
| -rw-r--r-- | arch/parisc/include/asm/rtc.h | 131 |
3 files changed, 146 insertions, 140 deletions
diff --git a/arch/parisc/include/asm/hash.h b/arch/parisc/include/asm/hash.h new file mode 100644 index 000000000000..dbe93311aa26 --- /dev/null +++ b/arch/parisc/include/asm/hash.h @@ -0,0 +1,146 @@ +#ifndef _ASM_HASH_H +#define _ASM_HASH_H + +/* + * HP-PA only implements integer multiply in the FPU. However, for + * integer multiplies by constant, it has a number of shift-and-add + * (but no shift-and-subtract, sigh!) instructions that a compiler + * can synthesize a code sequence with. + * + * Unfortunately, GCC isn't very efficient at using them. For example + * it uses three instructions for "x *= 21" when only two are needed. + * But we can find a sequence manually. + */ + +#define HAVE_ARCH__HASH_32 1 + +/* + * This is a multiply by GOLDEN_RATIO_32 = 0x61C88647 optimized for the + * PA7100 pairing rules. This is an in-order 2-way superscalar processor. + * Only one instruction in a pair may be a shift (by more than 3 bits), + * but other than that, simple ALU ops (including shift-and-add by up + * to 3 bits) may be paired arbitrarily. + * + * PA8xxx processors also dual-issue ALU instructions, although with + * fewer constraints, so this schedule is good for them, too. + * + * This 6-step sequence was found by Yevgen Voronenko's implementation + * of the Hcub algorithm at http://spiral.ece.cmu.edu/mcm/gen.html. + */ +static inline u32 __attribute_const__ __hash_32(u32 x) +{ + u32 a, b, c; + + /* + * Phase 1: Compute a = (x << 19) + x, + * b = (x << 9) + a, c = (x << 23) + b. + */ + a = x << 19; /* Two shifts can't be paired */ + b = x << 9; a += x; + c = x << 23; b += a; + c += b; + /* Phase 2: Return (b<<11) + (c<<6) + (a<<3) - c */ + b <<= 11; + a += c << 3; b -= c; + return (a << 3) + b; +} + +#if BITS_PER_LONG == 64 + +#define HAVE_ARCH_HASH_64 1 + +/* + * Finding a good shift-and-add chain for GOLDEN_RATIO_64 is tricky, + * because available software for the purpose chokes on constants this + * large. (It's mostly designed for compiling FIR filter coefficients + * into FPGAs.) + * + * However, Jason Thong pointed out a work-around. The Hcub software + * (http://spiral.ece.cmu.edu/mcm/gen.html) is designed for *multiple* + * constant multiplication, and is good at finding shift-and-add chains + * which share common terms. + * + * Looking at 0x0x61C8864680B583EB in binary: + * 0110000111001000100001100100011010000000101101011000001111101011 + * \______________/ \__________/ \_______/ \________/ + * \____________________________/ \____________________/ + * you can see the non-zero bits are divided into several well-separated + * blocks. Hcub can find algorithms for those terms separately, which + * can then be shifted and added together. + * + * Dividing the input into 2, 3 or 4 blocks, Hcub can find solutions + * with 10, 9 or 8 adds, respectively, making a total of 11 for the + * whole number. + * + * Using just two large blocks, 0xC3910C8D << 31 in the high bits, + * and 0xB583EB in the low bits, produces as good an algorithm as any, + * and with one more small shift than alternatives. + * + * The high bits are a larger number and more work to compute, as well + * as needing one extra cycle to shift left 31 bits before the final + * addition, so they are the critical path for scheduling. The low bits + * can fit into the scheduling slots left over. + */ + + +/* + * This _ASSIGN(dst, src) macro performs "dst = src", but prevents GCC + * from inferring anything about the value assigned to "dest". + * + * This prevents it from mis-optimizing certain sequences. + * In particular, gcc is annoyingly eager to combine consecutive shifts. + * Given "x <<= 19; y += x; z += x << 1;", GCC will turn this into + * "y += x << 19; z += x << 20;" even though the latter sequence needs + * an additional instruction and temporary register. + * + * Because no actual assembly code is generated, this construct is + * usefully portable across all GCC platforms, and so can be test-compiled + * on non-PA systems. + * + * In two places, additional unused input dependencies are added. This + * forces GCC's scheduling so it does not rearrange instructions too much. + * Because the PA-8xxx is out of order, I'm not sure how much this matters, + * but why make it more difficult for the processor than necessary? + */ +#define _ASSIGN(dst, src, ...) asm("" : "=r" (dst) : "0" (src), ##__VA_ARGS__) + +/* + * Multiply by GOLDEN_RATIO_64 = 0x0x61C8864680B583EB using a heavily + * optimized shift-and-add sequence. + * + * Without the final shift, the multiply proper is 19 instructions, + * 10 cycles and uses only 4 temporaries. Whew! + * + * You are not expected to understand this. + */ +static __always_inline u32 __attribute_const__ +hash_64(u64 a, unsigned int bits) +{ + u64 b, c, d; + + /* + * Encourage GCC to move a dynamic shift to %sar early, + * thereby freeing up an additional temporary register. + */ + if (!__builtin_constant_p(bits)) + asm("" : "=q" (bits) : "0" (64 - bits)); + else + bits = 64 - bits; + + _ASSIGN(b, a*5); c = a << 13; + b = (b << 2) + a; _ASSIGN(d, a << 17); + a = b + (a << 1); c += d; + d = a << 10; _ASSIGN(a, a << 19); + d = a - d; _ASSIGN(a, a << 4, "X" (d)); + c += b; a += b; + d -= c; c += a << 1; + a += c << 3; _ASSIGN(b, b << (7+31), "X" (c), "X" (d)); + a <<= 31; b += d; + a += b; + return a >> bits; +} +#undef _ASSIGN /* We're a widely-used header file, so don't litter! */ + +#endif /* BITS_PER_LONG == 64 */ + +#endif /* _ASM_HASH_H */ diff --git a/arch/parisc/include/asm/mc146818rtc.h b/arch/parisc/include/asm/mc146818rtc.h deleted file mode 100644 index adf41631449f..000000000000 --- a/arch/parisc/include/asm/mc146818rtc.h +++ /dev/null @@ -1,9 +0,0 @@ -/* - * Machine dependent access functions for RTC registers. - */ -#ifndef _ASM_MC146818RTC_H -#define _ASM_MC146818RTC_H - -/* empty include file to satisfy the include in genrtc.c */ - -#endif /* _ASM_MC146818RTC_H */ diff --git a/arch/parisc/include/asm/rtc.h b/arch/parisc/include/asm/rtc.h deleted file mode 100644 index 099d641a42c2..000000000000 --- a/arch/parisc/include/asm/rtc.h +++ /dev/null @@ -1,131 +0,0 @@ -/* - * include/asm-parisc/rtc.h - * - * Copyright 2002 Randolph CHung <tausq@debian.org> - * - * Based on: include/asm-ppc/rtc.h and the genrtc driver in the - * 2.4 parisc linux tree - */ - -#ifndef __ASM_RTC_H__ -#define __ASM_RTC_H__ - -#ifdef __KERNEL__ - -#include <linux/rtc.h> - -#include <asm/pdc.h> - -#define SECS_PER_HOUR (60 * 60) -#define SECS_PER_DAY (SECS_PER_HOUR * 24) - - -#define RTC_PIE 0x40 /* periodic interrupt enable */ -#define RTC_AIE 0x20 /* alarm interrupt enable */ -#define RTC_UIE 0x10 /* update-finished interrupt enable */ - -#define RTC_BATT_BAD 0x100 /* battery bad */ - -/* some dummy definitions */ -#define RTC_SQWE 0x08 /* enable square-wave output */ -#define RTC_DM_BINARY 0x04 /* all time/date values are BCD if clear */ -#define RTC_24H 0x02 /* 24 hour mode - else hours bit 7 means pm */ -#define RTC_DST_EN 0x01 /* auto switch DST - works f. USA only */ - -# define __isleap(year) \ - ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0)) - -/* How many days come before each month (0-12). */ -static const unsigned short int __mon_yday[2][13] = -{ - /* Normal years. */ - { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }, - /* Leap years. */ - { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 } -}; - -static inline unsigned int get_rtc_time(struct rtc_time *wtime) -{ - struct pdc_tod tod_data; - long int days, rem, y; - const unsigned short int *ip; - - memset(wtime, 0, sizeof(*wtime)); - if (pdc_tod_read(&tod_data) < 0) - return RTC_24H | RTC_BATT_BAD; - - // most of the remainder of this function is: -// Copyright (C) 1991, 1993, 1997, 1998 Free Software Foundation, Inc. -// This was originally a part of the GNU C Library. -// It is distributed under the GPL, and was swiped from offtime.c - - - days = tod_data.tod_sec / SECS_PER_DAY; - rem = tod_data.tod_sec % SECS_PER_DAY; - - wtime->tm_hour = rem / SECS_PER_HOUR; - rem %= SECS_PER_HOUR; - wtime->tm_min = rem / 60; - wtime->tm_sec = rem % 60; - - y = 1970; - -#define DIV(a, b) ((a) / (b) - ((a) % (b) < 0)) -#define LEAPS_THRU_END_OF(y) (DIV (y, 4) - DIV (y, 100) + DIV (y, 400)) - - while (days < 0 || days >= (__isleap (y) ? 366 : 365)) - { - /* Guess a corrected year, assuming 365 days per year. */ - long int yg = y + days / 365 - (days % 365 < 0); - - /* Adjust DAYS and Y to match the guessed year. */ - days -= ((yg - y) * 365 - + LEAPS_THRU_END_OF (yg - 1) - - LEAPS_THRU_END_OF (y - 1)); - y = yg; - } - wtime->tm_year = y - 1900; - - ip = __mon_yday[__isleap(y)]; - for (y = 11; days < (long int) ip[y]; --y) - continue; - days -= ip[y]; - wtime->tm_mon = y; - wtime->tm_mday = days + 1; - - return RTC_24H; -} - -static int set_rtc_time(struct rtc_time *wtime) -{ - u_int32_t secs; - - secs = mktime(wtime->tm_year + 1900, wtime->tm_mon + 1, wtime->tm_mday, - wtime->tm_hour, wtime->tm_min, wtime->tm_sec); - - if(pdc_tod_set(secs, 0) < 0) - return -1; - else - return 0; - -} - -static inline unsigned int get_rtc_ss(void) -{ - struct rtc_time h; - - get_rtc_time(&h); - return h.tm_sec; -} - -static inline int get_rtc_pll(struct rtc_pll_info *pll) -{ - return -EINVAL; -} -static inline int set_rtc_pll(struct rtc_pll_info *pll) -{ - return -EINVAL; -} - -#endif /* __KERNEL__ */ -#endif /* __ASM_RTC_H__ */ |