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<a name="l00364"></a>00364 <span class="comment">// Q <= actual quotient, so fix it</span><a name="l00365"></a>00365 <span class="keywordflow">while</span> (A[2] || A[1] > B1 || (A[1]==B1 && A[0]>=B0))<a name="l00366"></a>00366 {<a name="l00367"></a>00367 u = (D) A[0] - B0;<a name="l00368"></a>00368 A[0] = u.GetLowHalf();<a name="l00369"></a>00369 u = (D) A[1] - B1 - u.GetHighHalfAsBorrow();<a name="l00370"></a>00370 A[1] = u.GetLowHalf();<a name="l00371"></a>00371 A[2] += u.GetHighHalf();<a name="l00372"></a>00372 Q++;<a name="l00373"></a>00373 assert(Q); <span class="comment">// shouldn't overflow</span><a name="l00374"></a>00374 }<a name="l00375"></a>00375 <a name="l00376"></a>00376 <span class="keywordflow">return</span> Q;<a name="l00377"></a>00377 }<a name="l00378"></a>00378 <a name="l00379"></a>00379 <span class="comment">// do a 4 word by 2 word divide, returns 2 word quotient in Q0 and Q1</span><a name="l00380"></a>00380 <span class="keyword">template</span> <<span class="keyword">class</span> S, <span class="keyword">class</span> D><a name="l00381"></a>00381 <span class="keyword">inline</span> D DivideFourWordsByTwo(S *T, <span class="keyword">const</span> D &Al, <span class="keyword">const</span> D &Ah, <span class="keyword">const</span> D &B)<a name="l00382"></a>00382 {<a name="l00383"></a>00383 <span class="keywordflow">if</span> (!B) <span class="comment">// if divisor is 0, we assume divisor==2**(2*WORD_BITS)</span><a name="l00384"></a>00384 <span class="keywordflow">return</span> D(Ah.GetLowHalf(), Ah.GetHighHalf());<a name="l00385"></a>00385 <span class="keywordflow">else</span><a name="l00386"></a>00386 {<a name="l00387"></a>00387 S Q[2];<a name="l00388"></a>00388 T[0] = Al.GetLowHalf();<a name="l00389"></a>00389 T[1] = Al.GetHighHalf(); <a name="l00390"></a>00390 T[2] = Ah.GetLowHalf();<a name="l00391"></a>00391 T[3] = Ah.GetHighHalf();<a name="l00392"></a>00392 Q[1] = DivideThreeWordsByTwo<S, D>(T+1, B.GetLowHalf(), B.GetHighHalf());<a name="l00393"></a>00393 Q[0] = DivideThreeWordsByTwo<S, D>(T, B.GetLowHalf(), B.GetHighHalf());<a name="l00394"></a>00394 <span class="keywordflow">return</span> D(Q[0], Q[1]);<a name="l00395"></a>00395 }<a name="l00396"></a>00396 }<a name="l00397"></a>00397 <a name="l00398"></a>00398 <span class="comment">// returns quotient, which must fit in a word</span><a name="l00399"></a><a class="code" href="class_d_word.html#82597a869878e3924c9e7f03dc7ddcb1">00399</a> <span class="keyword">inline</span> word <a class="code" href="class_d_word.html#82597a869878e3924c9e7f03dc7ddcb1">DWord::operator/</a>(word a)<a name="l00400"></a>00400 {<a name="l00401"></a>00401 <span class="preprocessor"> #ifdef CRYPTOPP_NATIVE_DWORD_AVAILABLE</span><a name="l00402"></a>00402 <span class="preprocessor"></span> <span class="keywordflow">return</span> word(<a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">m_whole</a> / a);<a name="l00403"></a>00403 <span class="preprocessor"> #else</span><a name="l00404"></a>00404 <span class="preprocessor"></span> hword r[4];<a name="l00405"></a>00405 <span class="keywordflow">return</span> DivideFourWordsByTwo<hword, Word>(r, m_halfs.low, m_halfs.high, a).GetWhole();<a name="l00406"></a>00406 <span class="preprocessor"> #endif</span><a name="l00407"></a>00407 <span class="preprocessor"></span>}<a name="l00408"></a>00408 <a name="l00409"></a><a class="code" href="class_d_word.html#9dd87373f7a654e7fec14c7bc147f3eb">00409</a> <span class="keyword">inline</span> word <a class="code" href="class_d_word.html#9dd87373f7a654e7fec14c7bc147f3eb">DWord::operator%</a>(word a)<a name="l00410"></a>00410 {<a name="l00411"></a>00411 <span class="preprocessor"> #ifdef CRYPTOPP_NATIVE_DWORD_AVAILABLE</span><a name="l00412"></a>00412 <span class="preprocessor"></span> <span class="keywordflow">return</span> word(<a class="code" href="class_d_word.html#f1503dcbfece6416389ad1ff69a0c10b">m_whole</a> % a);<a name="l00413"></a>00413 <span class="preprocessor"> #else</span><a name="l00414"></a>00414 <span class="preprocessor"></span> <span class="keywordflow">if</span> (a < (word(1) << (WORD_BITS/2)))<a name="l00415"></a>00415 {<a name="l00416"></a>00416 hword h = hword(a);<a name="l00417"></a>00417 word r = m_halfs.high % h;<a name="l00418"></a>00418 r = ((m_halfs.low >> (WORD_BITS/2)) + (r << (WORD_BITS/2))) % h;<a name="l00419"></a>00419 <span class="keywordflow">return</span> hword((hword(m_halfs.low) + (r << (WORD_BITS/2))) % h);<a name="l00420"></a>00420 }<a name="l00421"></a>00421 <span class="keywordflow">else</span><a name="l00422"></a>00422 {<a name="l00423"></a>00423 hword r[4];<a name="l00424"></a>00424 DivideFourWordsByTwo<hword, Word>(r, m_halfs.low, m_halfs.high, a);<a name="l00425"></a>00425 <span class="keywordflow">return</span> <a class="code" href="class_word.html">Word</a>(r[0], r[1]).GetWhole();<a name="l00426"></a>00426 }<a name="l00427"></a>00427 <span class="preprocessor"> #endif</span><a name="l00428"></a>00428 <span class="preprocessor"></span>}<a name="l00429"></a>00429 <a name="l00430"></a>00430 <span class="comment">// ********************************************************</span><a name="l00431"></a>00431 <a name="l00432"></a>00432 <span class="comment">// use some tricks to share assembly code between MSVC and GCC</span><a name="l00433"></a>00433 <span class="preprocessor">#if defined(__GNUC__)</span><a name="l00434"></a>00434 <span class="preprocessor"></span><span class="preprocessor"> #define AddPrologue \</span><a name="l00435"></a>00435 <span class="preprocessor"> int result; \</span><a name="l00436"></a>00436 <span class="preprocessor"> __asm__ __volatile__ \</span><a name="l00437"></a>00437 <span class="preprocessor"> ( \</span><a name="l00438"></a>00438 <span class="preprocessor"> ".intel_syntax noprefix;"</span><a name="l00439"></a>00439 <span class="preprocessor"></span><span class="preprocessor"> #define AddEpilogue \</span><a name="l00440"></a>00440 <span class="preprocessor"> ".att_syntax prefix;" \</span><a name="l00441"></a>00441 <span class="preprocessor"> : "=a" (result)\</span><a name="l00442"></a>00442 <span class="preprocessor"> : "d" (C), "a" (A), "D" (B), "c" (N) \</span><a name="l00443"></a>00443 <span class="preprocessor"> : "%esi", "memory", "cc" \</span><a name="l00444"></a>00444 <span class="preprocessor"> );\</span><a name="l00445"></a>00445 <span class="preprocessor"> return result;</span><a name="l00446"></a>00446 <span class="preprocessor"></span><span class="preprocessor"> #define MulPrologue \</span><a name="l00447"></a>00447 <span class="preprocessor"> __asm__ __volatile__ \</span><a name="l00448"></a>00448 <span class="preprocessor"> ( \</span><a name="l00449"></a>00449 <span class="preprocessor"> ".intel_syntax noprefix;" \</span><a name="l00450"></a>00450 <span class="preprocessor"> AS1( push ebx) \</span><a name="l00451"></a>00451 <span class="preprocessor"> AS2( mov ebx, edx)</span><a name="l00452"></a>00452 <span class="preprocessor"></span><span class="preprocessor"> #define MulEpilogue \</span><a name="l00453"></a>00453 <span class="preprocessor"> AS1( pop ebx) \</span><a name="l00454"></a>00454 <span class="preprocessor"> ".att_syntax prefix;" \</span><a name="l00455"></a>00455 <span class="preprocessor"> : \</span><a name="l00456"></a>00456 <span class="preprocessor"> : "d" (s_maskLow16), "c" (C), "a" (A), "D" (B) \</span><a name="l00457"></a>00457 <span class="preprocessor"> : "%esi", "memory", "cc" \</span><a name="l00458"></a>00458 <span class="preprocessor"> );</span><a name="l00459"></a>00459 <span class="preprocessor"></span><span class="preprocessor"> #define SquPrologue MulPrologue</span><a name="l00460"></a>00460 <span class="preprocessor"></span><span class="preprocessor"> #define SquEpilogue \</span><a name="l00461"></a>00461 <span class="preprocessor"> AS1( pop ebx) \</span><a name="l00462"></a>00462 <span class="preprocessor"> ".att_syntax prefix;" \</span><a name="l00463"></a>00463 <span class="preprocessor"> : \</span><a name="l00464"></a>00464 <span class="preprocessor"> : "d" (s_maskLow16), "c" (C), "a" (A) \</span><a name="l00465"></a>00465 <span class="preprocessor"> : "%esi", "%edi", "memory", "cc" \</span><a name="l00466"></a>00466 <span class="preprocessor"> );</span><a name="l00467"></a>00467 <span class="preprocessor"></span><span class="preprocessor"> #define TopPrologue MulPrologue</span><a name="l00468"></a>00468 <span class="preprocessor"></span><span class="preprocessor"> #define TopEpilogue \</span><a name="l00469"></a>00469 <span class="preprocessor"> AS1( pop ebx) \</span><a name="l00470"></a>00470 <span class="preprocessor"> ".att_syntax prefix;" \</span><a name="l00471"></a>00471 <span class="preprocessor"> : \</span><a name="l00472"></a>00472 <span class="preprocessor"> : "d" (s_maskLow16), "c" (C), "a" (A), "D" (B), "S" (L) \</span><a name="l00473"></a>00473 <span class="preprocessor"> : "memory", "cc" \</span><a name="l00474"></a>00474 <span class="preprocessor"> );</span><a name="l00475"></a>00475 <span class="preprocessor"></span><span class="preprocessor">#else</span><a name="l00476"></a>00476 <span class="preprocessor"></span><span class="preprocessor"> #define AddPrologue \</span><a name="l00477"></a>00477 <span class="preprocessor"> __asm push edi \</span><a name="l00478"></a>00478 <span class="preprocessor"> __asm push esi \</span><a name="l00479"></a>00479 <span class="preprocessor"> __asm mov eax, [esp+12] \</span><a name="l00480"></a>00480 <span class="preprocessor"> __asm mov edi, [esp+16]</span><a name="l00481"></a>00481 <span class="preprocessor"></span><span class="preprocessor"> #define AddEpilogue \</span><a name="l00482"></a>00482 <span class="preprocessor"> __asm pop esi \</span><a name="l00483"></a>00483 <span class="preprocessor"> __asm pop edi \</span><a name="l00484"></a>00484 <span class="preprocessor"> __asm ret 8</span><a name="l00485"></a>00485 <span class="preprocessor"></span><span class="preprocessor">#if _MSC_VER < 1300</span><a name="l00486"></a>00486 <span class="preprocessor"></span><span class="preprocessor"> #define SaveEBX __asm push ebx</span><a name="l00487"></a>00487 <span class="preprocessor"></span><span class="preprocessor"> #define RestoreEBX __asm pop ebx</span><a name="l00488"></a>00488 <span class="preprocessor"></span><span class="preprocessor">#else</span><a name="l00489"></a>00489 <span class="preprocessor"></span><span class="preprocessor"> #define SaveEBX</span><a name="l00490"></a>00490 <span class="preprocessor"></span><span class="preprocessor"> #define RestoreEBX</span><a name="l00491"></a>00491 <span class="preprocessor"></span><span class="preprocessor">#endif</span>⌨️ 快捷键说明
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