/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _ASM_HASH_H #define _ASM_HASH_H /* * The later H8SX models have a 32x32-bit multiply, but the H8/300H * and H8S have only 16x16->32. Since it's tolerably compact, this is * basically an inlined version of the __mulsi3 code. Since the inputs * are not expected to be small, it's also simplfied by skipping the * early-out checks. * * (Since neither CPU has any multi-bit shift instructions, a * shift-and-add version is a non-starter.) * * TODO: come up with an arch-specific version of the hashing in fs/namei.c, * since that is heavily dependent on rotates. Which, as mentioned, suck * horribly on H8. */ #if defined(CONFIG_CPU_H300H) || defined(CONFIG_CPU_H8S) #define HAVE_ARCH__HASH_32 1 /* * Multiply by k = 0x61C88647. Fitting this into three registers requires * one extra instruction, but reducing register pressure will probably * make that back and then some. * * GCC asm note: %e1 is the high half of operand %1, while %f1 is the * low half. So if %1 is er4, then %e1 is e4 and %f1 is r4. * * This has been designed to modify x in place, since that's the most * common usage, but preserve k, since hash_64() makes two calls in * quick succession. */ static inline u32 __attribute_const__ __hash_32(u32 x) { u32 temp; asm( "mov.w %e1,%f0" "\n mulxu.w %f2,%0" /* klow * xhigh */ "\n mov.w %f0,%e1" /* The extra instruction */ "\n mov.w %f1,%f0" "\n mulxu.w %e2,%0" /* khigh * xlow */ "\n add.w %e1,%f0" "\n mulxu.w %f2,%1" /* klow * xlow */ "\n add.w %f0,%e1" : "=&r" (temp), "=r" (x) : "%r" (GOLDEN_RATIO_32), "1" (x)); return x; } #endif #endif /* _ASM_HASH_H */
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atomic.h | File | 2.47 KB | 0644 |
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bitops.h | File | 4.45 KB | 0644 |
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bug.h | File | 263 B | 0644 |
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byteorder.h | File | 148 B | 0644 |
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dma-mapping.h | File | 269 B | 0644 |
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elf.h | File | 2.66 KB | 0644 |
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flat.h | File | 1.1 KB | 0644 |
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hash.h | File | 1.63 KB | 0644 |
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io.h | File | 1.44 KB | 0644 |
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irq.h | File | 555 B | 0644 |
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irqflags.h | File | 1.88 KB | 0644 |
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page_offset.h | File | 37 B | 0644 |
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pci.h | File | 421 B | 0644 |
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pgtable.h | File | 1.7 KB | 0644 |
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processor.h | File | 3.17 KB | 0644 |
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ptrace.h | File | 1.03 KB | 0644 |
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segment.h | File | 886 B | 0644 |
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signal.h | File | 520 B | 0644 |
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smp.h | File | 32 B | 0644 |
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string.h | File | 389 B | 0644 |
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switch_to.h | File | 1.72 KB | 0644 |
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syscall.h | File | 1.03 KB | 0644 |
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thread_info.h | File | 3.26 KB | 0644 |
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tlb.h | File | 166 B | 0644 |
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traps.h | File | 1.06 KB | 0644 |
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uaccess.h | File | 1.02 KB | 0644 |
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user.h | File | 3.34 KB | 0644 |
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