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* optimization in the 8087/80287 version of fpc_arctan_real(): when calculating

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arctan([-]1/d), use fxch to swap the two arguments, instead of using fdivr,
  since fpatan can do the division for free

git-svn-id: trunk@26227 -
This commit is contained in:
nickysn 2013-12-13 01:24:01 +00:00
parent a7b4953795
commit c88be4550d
1 changed files with 2 additions and 2 deletions
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4
rtl/i8086/math.inc
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@ -132,7 +132,7 @@
@@greater_than_one: @@greater_than_one:
{ d > 1 } { d > 1 }
fdivr st(1), st // 1 1/d fxch st(1) // d 1
fpatan // arctan(1/d) fpatan // arctan(1/d)
fld tbyte [Extended_PIO2] // pi/2 arctan(1/d) fld tbyte [Extended_PIO2] // pi/2 arctan(1/d)
fsubrp st(1), st // pi/2-arctan(1/d) fsubrp st(1), st // pi/2-arctan(1/d)
@ -171,7 +171,7 @@
@@less_than_minus_one: @@less_than_minus_one:
{ d < -1; -d > 1 } { d < -1; -d > 1 }
fdivr st(1), st // 1 -1/d fxch st(1) // -d 1
fpatan // arctan(-1/d) fpatan // arctan(-1/d)
fld tbyte [Extended_PIO2] // pi/2 arctan(-1/d) fld tbyte [Extended_PIO2] // pi/2 arctan(-1/d)
fsubp st(1), st // arctan(-1/d)-pi/2 fsubp st(1), st // arctan(-1/d)-pi/2