mirror of
https://github.com/ioacademy-jikim/debugging
synced 2025-06-10 09:26:15 +00:00
67 lines
1.5 KiB
C
67 lines
1.5 KiB
C
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#include <stdio.h>
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typedef unsigned long long int ULong;
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typedef unsigned int UInt;
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__attribute__((noinline))
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void do_lzcnt32 ( /*OUT*/UInt* flags, /*OUT*/UInt* res, UInt arg )
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{
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UInt block[3] = { arg, 0, 0 };
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__asm__ __volatile__(
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"movl $0x55555555, %%esi" "\n\t"
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"lzcntl 0(%0), %%esi" "\n\t"
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"movl %%esi, 4(%0)" "\n\t"
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"pushfl" "\n\t"
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"popl %%esi" "\n\t"
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"movl %%esi, 8(%0)" "\n"
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: : "r"(&block[0]) : "esi","cc","memory"
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);
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*res = block[1];
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*flags = block[2] & 0x8d5;
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}
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__attribute__((noinline))
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void do_lzcnt16 ( /*OUT*/UInt* flags, /*OUT*/UInt* res, UInt arg )
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{
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UInt block[3] = { arg, 0, 0 };
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__asm__ __volatile__(
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"movl $0x55555555, %%esi" "\n\t"
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"lzcntw 0(%0), %%si" "\n\t"
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"movl %%esi, 4(%0)" "\n\t"
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"pushfl" "\n\t"
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"popl %%esi" "\n\t"
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"movl %%esi, 8(%0)" "\n"
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: : "r"(&block[0]) : "esi","cc","memory"
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);
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*res = block[1];
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*flags = block[2] & 0x8d5;
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}
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int main ( void )
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{
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UInt w;
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w = 0xFEDC1928;
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while (1) {
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UInt res;
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UInt flags;
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do_lzcnt32(&flags, &res, w);
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printf("lzcntl %08x -> %08x %04x\n", w, res, flags);
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if (w == 0) break;
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w = ((w >> 2) | (w >> 1)) + (w / 17);
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}
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w = 0xFEDC1928;
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while (1) {
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UInt res;
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UInt flags;
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do_lzcnt16(&flags, &res, w);
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printf("lzcntw %08x -> %08x %04x\n", w, res, flags);
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if (w == 0) break;
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w = ((w >> 2) | (w >> 1)) + (w / 17);
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}
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return 0;
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}
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