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Clean up comment at start of fpc_mul_dword

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git-svn-id: trunk@26368 -
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pierre 2014-01-03 13:15:34 +00:00
parent ab4844bdff
commit de89827eb7
1 changed files with 4 additions and 8 deletions
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12
rtl/i8086/int32p.inc
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@ -18,19 +18,15 @@ function fpc_mul_dword( f1, f2: dword; checkoverflow: boolean ): dword; [public,
begin begin
{ routine contributed by Max Nazhalov { routine contributed by Max Nazhalov
//////// 16-bit multiplications summary: 32-bit multiplications summary:
(A1:A0*B1:B0) = (A1*B1)<<32 + (A1*B0)<<16 + (A0*B1)<<16 + (A0*B0) f1 = A1*$10000+A0
f2 = B1*$10000+B0
(A1:A0*B1:B0) = (A1*B1)<<32 + (A1*B0)<<16 + (A0*B1)<<16 + (A0*B0)
A1*B1 [only needed for overflow checking; overflow if <>0] A1*B1 [only needed for overflow checking; overflow if <>0]
A1*B0 A1*B0
A0*B1 A0*B1
A0:B0 A0:B0
A3*B0 [only lo_word is needed; overflow if hi_word<>0]
A2*B1 [only lo_word is needed; overflow if hi_word<>0]
A2*B0
A1*B2 [only lo_word is needed; overflow if hi_word<>0]
A0*B3 [only lo_word is needed; overflow if hi_word<>0]
A0*B2
} }
asm asm
mov cx,word[f1] mov cx,word[f1]