77 lines
2.7 KiB
C
77 lines
2.7 KiB
C
/*
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* |-----------------------------------------------------------|
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* | Copyright (c) 1991 MIPS Computer Systems, Inc. |
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* | All Rights Reserved |
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* |-----------------------------------------------------------|
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* | Restricted Rights Legend |
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* | Use, duplication, or disclosure by the Government is |
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* | subject to restrictions as set forth in |
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* | subparagraph (c)(1)(ii) of the Rights in Technical |
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* | Data and Computer Software Clause of DFARS 52.227-7013. |
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* | MIPS Computer Systems, Inc. |
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* | 950 DeGuigne Drive |
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* | Sunnyvale, CA 94086 |
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* |-----------------------------------------------------------|
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*/
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/*
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* NOTE : this routine and the lldefs.h header file came from
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* irix/lib/libc/src/math directory. Currently being used
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* by dmedia to resolve some problems with compiler undefines.
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* "__ll_bit_extract" and "__ll_bit_insert".
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*/
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#include <limits.h>
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#define BITS_PER_LONGLONG 64
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#include "lldefs.h"
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extern ulonglong_t
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__ll_bit_extract (ulonglong_t *addr, unsigned start_bit, unsigned length)
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{
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/* assume 32 < length < 64 */
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unsigned words = start_bit / BITS_PER_LONGLONG;
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unsigned lbits = start_bit % BITS_PER_LONGLONG;
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unsigned rbits = BITS_PER_LONGLONG - (lbits + length);
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llvalue llval, addrval, mask, one;
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addr += words;
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addrval.ull = *addr;
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SET_LL(one, 1);
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SET_LL(mask, 1);
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mask.ull = __ll_lshift(mask.ull, length);
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LL_SUB(mask, mask, one);
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mask.ull = __ll_lshift(mask.ull, rbits); /* all 1's in field */
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LL_AND(llval, addrval, mask);
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/* shift to left so will sign-extend */
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llval.ull = __ll_lshift(llval.ull, lbits);
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llval.ull = __ll_rshift(llval.ull, lbits+rbits);
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return llval.ull;
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}
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extern ulonglong_t
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__ll_bit_insert (ulonglong_t *addr, unsigned start_bit, unsigned length, ulonglong_t val)
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{
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/* assume 32 < length < 64 */
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unsigned words = start_bit / BITS_PER_LONGLONG;
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unsigned lbits = start_bit % BITS_PER_LONGLONG;
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unsigned rbits = BITS_PER_LONGLONG - (lbits + length);
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llvalue llval, addrval, mask, nmask, one;
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addr += words;
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llval.ull = val;
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addrval.ull = *addr;
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SET_LL(one, 1);
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SET_LL(mask, 1);
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mask.ull = __ll_lshift(mask.ull, length);
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LL_SUB(mask, mask, one);
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mask.ull = __ll_lshift(mask.ull, rbits); /* all 1's in field */
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LL_NOT(nmask, mask);
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LL_AND(addrval, addrval, nmask); /* clear the field */
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llval.ull = __ll_lshift(llval.ull, lbits+rbits);/* clear lhs, rhs */
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llval.ull = __ull_rshift(llval.ull, lbits);
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LL_OR(addrval, addrval, llval);
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*addr = addrval.ull;
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llval.ull = __ull_rshift(llval.ull, rbits); /* truncated val */
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return llval.ull;
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}
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