/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_HASH_H #define _ASM_HASH_H /* * If CONFIG_M68000=y (original mc68000/010), this file is #included * to work around the lack of a MULU.L instruction. */ #define HAVE_ARCH__HASH_32 1 /* * While it would be legal to substitute a different hash operation * entirely, let's keep it simple and just use an optimized multiply * by GOLDEN_RATIO_32 = 0x61C88647. * * The best way to do that appears to be to multiply by 0x8647 with * shifts and adds, and use mulu.w to multiply the high half by 0x61C8. * * Because the 68000 has multi-cycle shifts, this addition chain is * chosen to minimise the shift distances. * * Despite every attempt to spoon-feed it simple operations, GCC * 6.1.1 doggedly insists on doing annoying things like converting * "lsl.l #2,<reg>" (12 cycles) to two adds (8+8 cycles). * * It also likes to notice two shifts in a row, like "a = x << 2" and * "a <<= 7", and convert that to "a = x << 9". But shifts longer * than 8 bits are extra-slow on m68k, so that's a lose. * * Since the 68000 is a very simple in-order processor with no * instruction scheduling effects on execution time, we can safely * take it out of GCC's hands and write one big asm() block. * * Without calling overhead, this operation is 30 bytes (14 instructions * plus one immediate constant) and 166 cycles. * * (Because %2 is fetched twice, it can't be postincrement, and thus it * can't be a fully general "g" or "m". Register is preferred, but * offsettable memory or immediate will work.) */ static inline u32 __attribute_const__ __hash_32(u32 x) { u32 a, b; asm( "move.l %2,%0" /* a = x * 0x0001 */ "\n lsl.l #2,%0" /* a = x * 0x0004 */ "\n move.l %0,%1" "\n lsl.l #7,%0" /* a = x * 0x0200 */ "\n add.l %2,%0" /* a = x * 0x0201 */ "\n add.l %0,%1" /* b = x * 0x0205 */ "\n add.l %0,%0" /* a = x * 0x0402 */ "\n add.l %0,%1" /* b = x * 0x0607 */ "\n lsl.l #5,%0" /* a = x * 0x8040 */ : "=&d,d" (a), "=&r,r" (b) : "r,roi?" (x)); /* a+b = x*0x8647 */ return ((u16)(x*0x61c8) << 16) + a + b; } #endif /* _ASM_HASH_H */
Name | Type | Size | Permission | Actions |
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Kbuild | File | 599 B | 0644 |
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MC68328.h | File | 37.82 KB | 0644 |
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MC68EZ328.h | File | 37.74 KB | 0644 |
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MC68VZ328.h | File | 41.02 KB | 0644 |
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a.out-core.h | File | 1.98 KB | 0644 |
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adb_iop.h | File | 1.09 KB | 0644 |
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amigahw.h | File | 10.49 KB | 0644 |
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amigaints.h | File | 3.5 KB | 0644 |
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amigayle.h | File | 3.19 KB | 0644 |
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amipcmcia.h | File | 2.51 KB | 0644 |
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apollohw.h | File | 2.35 KB | 0644 |
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asm-offsets.h | File | 35 B | 0644 |
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asm-prototypes.h | File | 211 B | 0644 |
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atafd.h | File | 300 B | 0644 |
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atafdreg.h | File | 2.68 KB | 0644 |
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atari_joystick.h | File | 457 B | 0644 |
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atari_stdma.h | File | 514 B | 0644 |
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atari_stram.h | File | 528 B | 0644 |
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atarihw.h | File | 20.3 KB | 0644 |
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atariints.h | File | 5.56 KB | 0644 |
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atarikb.h | File | 1.4 KB | 0644 |
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atomic.h | File | 4.86 KB | 0644 |
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bitops.h | File | 12.19 KB | 0644 |
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blinken.h | File | 641 B | 0644 |
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bootinfo.h | File | 783 B | 0644 |
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bootstd.h | File | 4.64 KB | 0644 |
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bug.h | File | 659 B | 0644 |
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bugs.h | File | 369 B | 0644 |
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bvme6000hw.h | File | 3.45 KB | 0644 |
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cache.h | File | 296 B | 0644 |
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cacheflush.h | File | 133 B | 0644 |
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cacheflush_mm.h | File | 6.92 KB | 0644 |
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cacheflush_no.h | File | 2.61 KB | 0644 |
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checksum.h | File | 3.4 KB | 0644 |
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cmpxchg.h | File | 3.34 KB | 0644 |
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coldfire.h | File | 1.61 KB | 0644 |
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contregs.h | File | 3.31 KB | 0644 |
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current.h | File | 580 B | 0644 |
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delay.h | File | 3.43 KB | 0644 |
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div64.h | File | 858 B | 0644 |
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dma-mapping.h | File | 291 B | 0644 |
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dma.h | File | 16.65 KB | 0644 |
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dsp56k.h | File | 1.24 KB | 0644 |
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dvma.h | File | 9.67 KB | 0644 |
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elf.h | File | 3.07 KB | 0644 |
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entry.h | File | 5.76 KB | 0644 |
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export.h | File | 74 B | 0644 |
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fb.h | File | 921 B | 0644 |
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fbio.h | File | 9.87 KB | 0644 |
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flat.h | File | 1.02 KB | 0644 |
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floppy.h | File | 5.06 KB | 0644 |
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fpu.h | File | 535 B | 0644 |
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ftrace.h | File | 12 B | 0644 |
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gpio.h | File | 2.64 KB | 0644 |
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hardirq.h | File | 594 B | 0644 |
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hash.h | File | 2.07 KB | 0644 |
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hp300hw.h | File | 186 B | 0644 |
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hwtest.h | File | 467 B | 0644 |
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ide.h | File | 1.67 KB | 0644 |
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idprom.h | File | 725 B | 0644 |
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intersil.h | File | 1.11 KB | 0644 |
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io.h | File | 383 B | 0644 |
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io_mm.h | File | 16.19 KB | 0644 |
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io_no.h | File | 5.26 KB | 0644 |
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irq.h | File | 2.57 KB | 0644 |
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irqflags.h | File | 1.61 KB | 0644 |
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kexec.h | File | 732 B | 0644 |
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linkage.h | File | 1.55 KB | 0644 |
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m5206sim.h | File | 6.4 KB | 0644 |
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m520xsim.h | File | 7.15 KB | 0644 |
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m523xsim.h | File | 7.7 KB | 0644 |
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m525xsim.h | File | 10.57 KB | 0644 |
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m5272sim.h | File | 6.05 KB | 0644 |
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m527xsim.h | File | 13.51 KB | 0644 |
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m528xsim.h | File | 9.37 KB | 0644 |
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m52xxacr.h | File | 3.57 KB | 0644 |
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m5307sim.h | File | 7.52 KB | 0644 |
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m53xxacr.h | File | 3.6 KB | 0644 |
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m53xxsim.h | File | 53.97 KB | 0644 |
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m5407sim.h | File | 6.14 KB | 0644 |
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m5441xsim.h | File | 8.5 KB | 0644 |
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m54xxacr.h | File | 4.82 KB | 0644 |
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m54xxgpt.h | File | 3.66 KB | 0644 |
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m54xxpci.h | File | 6.13 KB | 0644 |
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m54xxsim.h | File | 3.8 KB | 0644 |
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mac_asc.h | File | 520 B | 0644 |
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mac_baboon.h | File | 999 B | 0644 |
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mac_iop.h | File | 5.37 KB | 0644 |
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mac_oss.h | File | 1.83 KB | 0644 |
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mac_psc.h | File | 7.25 KB | 0644 |
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mac_via.h | File | 11.44 KB | 0644 |
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machdep.h | File | 1.34 KB | 0644 |
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machines.h | File | 3.13 KB | 0644 |
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machw.h | File | 588 B | 0644 |
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macintosh.h | File | 2.02 KB | 0644 |
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macints.h | File | 3.28 KB | 0644 |
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math-emu.h | File | 6.74 KB | 0644 |
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mc146818rtc.h | File | 598 B | 0644 |
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mcf8390.h | File | 3.75 KB | 0644 |
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mcf_pgalloc.h | File | 2.37 KB | 0644 |
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mcf_pgtable.h | File | 9.89 KB | 0644 |
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mcfclk.h | File | 1.01 KB | 0644 |
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mcfdma.h | File | 6.51 KB | 0644 |
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mcfgpio.h | File | 8.48 KB | 0644 |
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mcfintc.h | File | 3.09 KB | 0644 |
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mcfmmu.h | File | 3.67 KB | 0644 |
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mcfpit.h | File | 2.22 KB | 0644 |
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mcfqspi.h | File | 1.82 KB | 0644 |
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mcfsim.h | File | 1.5 KB | 0644 |
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mcfslt.h | File | 1.21 KB | 0644 |
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mcftimer.h | File | 2.3 KB | 0644 |
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mcfuart.h | File | 6.91 KB | 0644 |
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mcfwdebug.h | File | 4.99 KB | 0644 |
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mmu.h | File | 243 B | 0644 |
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mmu_context.h | File | 7.2 KB | 0644 |
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mmzone.h | File | 264 B | 0644 |
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module.h | File | 847 B | 0644 |
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motorola_pgalloc.h | File | 2.26 KB | 0644 |
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motorola_pgtable.h | File | 9.2 KB | 0644 |
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movs.h | File | 1.44 KB | 0644 |
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mvme147hw.h | File | 2.81 KB | 0644 |
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mvme16xhw.h | File | 2.16 KB | 0644 |
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natfeat.h | File | 533 B | 0644 |
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nettel.h | File | 2.95 KB | 0644 |
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nubus.h | File | 1.21 KB | 0644 |
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openprom.h | File | 7.98 KB | 0644 |
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oplib.h | File | 9.54 KB | 0644 |
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page.h | File | 1.47 KB | 0644 |
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page_mm.h | File | 4.06 KB | 0644 |
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page_no.h | File | 1.28 KB | 0644 |
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page_offset.h | File | 256 B | 0644 |
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parport.h | File | 837 B | 0644 |
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pci.h | File | 458 B | 0644 |
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pgalloc.h | File | 444 B | 0644 |
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pgtable.h | File | 127 B | 0644 |
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pgtable_mm.h | File | 4.84 KB | 0644 |
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pgtable_no.h | File | 1.57 KB | 0644 |
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processor.h | File | 3.59 KB | 0644 |
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ptrace.h | File | 643 B | 0644 |
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q40_master.h | File | 2.28 KB | 0644 |
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q40ints.h | File | 749 B | 0644 |
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quicc_simple.h | File | 1.79 KB | 0644 |
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raw_io.h | File | 11.41 KB | 0644 |
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segment.h | File | 1.42 KB | 0644 |
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serial.h | File | 1.14 KB | 0644 |
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setup.h | File | 9.25 KB | 0644 |
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signal.h | File | 1.34 KB | 0644 |
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smp.h | File | 32 B | 0644 |
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string.h | File | 1.68 KB | 0644 |
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sun3-head.h | File | 353 B | 0644 |
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sun3_pgalloc.h | File | 2.26 KB | 0644 |
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sun3_pgtable.h | File | 7.65 KB | 0644 |
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sun3ints.h | File | 989 B | 0644 |
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sun3mmu.h | File | 4.91 KB | 0644 |
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sun3x.h | File | 868 B | 0644 |
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sun3xflop.h | File | 5.62 KB | 0644 |
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sun3xprom.h | File | 1.31 KB | 0644 |
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switch_to.h | File | 1.51 KB | 0644 |
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thread_info.h | File | 2.02 KB | 0644 |
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timex.h | File | 974 B | 0644 |
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tlb.h | File | 486 B | 0644 |
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tlbflush.h | File | 5.95 KB | 0644 |
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traps.h | File | 8.33 KB | 0644 |
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uaccess.h | File | 152 B | 0644 |
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uaccess_mm.h | File | 10.31 KB | 0644 |
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uaccess_no.h | File | 3.69 KB | 0644 |
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ucontext.h | File | 570 B | 0644 |
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unaligned.h | File | 600 B | 0644 |
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unistd.h | File | 952 B | 0644 |
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user.h | File | 3.78 KB | 0644 |
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vga.h | File | 651 B | 0644 |
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virtconvert.h | File | 947 B | 0644 |
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zorro.h | File | 1.17 KB | 0644 |
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