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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/m68k/fpsp040/sacos.S | |
download | blackbird-op-linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz blackbird-op-linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/m68k/fpsp040/sacos.S')
-rw-r--r-- | arch/m68k/fpsp040/sacos.S | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/arch/m68k/fpsp040/sacos.S b/arch/m68k/fpsp040/sacos.S new file mode 100644 index 000000000000..83b00ab1c48f --- /dev/null +++ b/arch/m68k/fpsp040/sacos.S @@ -0,0 +1,115 @@ +| +| sacos.sa 3.3 12/19/90 +| +| Description: The entry point sAcos computes the inverse cosine of +| an input argument; sAcosd does the same except for denormalized +| input. +| +| Input: Double-extended number X in location pointed to +| by address register a0. +| +| Output: The value arccos(X) returned in floating-point register Fp0. +| +| Accuracy and Monotonicity: The returned result is within 3 ulps in +| 64 significant bit, i.e. within 0.5001 ulp to 53 bits if the +| result is subsequently rounded to double precision. The +| result is provably monotonic in double precision. +| +| Speed: The program sCOS takes approximately 310 cycles. +| +| Algorithm: +| +| ACOS +| 1. If |X| >= 1, go to 3. +| +| 2. (|X| < 1) Calculate acos(X) by +| z := (1-X) / (1+X) +| acos(X) = 2 * atan( sqrt(z) ). +| Exit. +| +| 3. If |X| > 1, go to 5. +| +| 4. (|X| = 1) If X > 0, return 0. Otherwise, return Pi. Exit. +| +| 5. (|X| > 1) Generate an invalid operation by 0 * infinity. +| Exit. +| + +| Copyright (C) Motorola, Inc. 1990 +| All Rights Reserved +| +| THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA +| The copyright notice above does not evidence any +| actual or intended publication of such source code. + +|SACOS idnt 2,1 | Motorola 040 Floating Point Software Package + + |section 8 + +PI: .long 0x40000000,0xC90FDAA2,0x2168C235,0x00000000 +PIBY2: .long 0x3FFF0000,0xC90FDAA2,0x2168C235,0x00000000 + + |xref t_operr + |xref t_frcinx + |xref satan + + .global sacosd +sacosd: +|--ACOS(X) = PI/2 FOR DENORMALIZED X + fmovel %d1,%fpcr | ...load user's rounding mode/precision + fmovex PIBY2,%fp0 + bra t_frcinx + + .global sacos +sacos: + fmovex (%a0),%fp0 | ...LOAD INPUT + + movel (%a0),%d0 | ...pack exponent with upper 16 fraction + movew 4(%a0),%d0 + andil #0x7FFFFFFF,%d0 + cmpil #0x3FFF8000,%d0 + bges ACOSBIG + +|--THIS IS THE USUAL CASE, |X| < 1 +|--ACOS(X) = 2 * ATAN( SQRT( (1-X)/(1+X) ) ) + + fmoves #0x3F800000,%fp1 + faddx %fp0,%fp1 | ...1+X + fnegx %fp0 | ... -X + fadds #0x3F800000,%fp0 | ...1-X + fdivx %fp1,%fp0 | ...(1-X)/(1+X) + fsqrtx %fp0 | ...SQRT((1-X)/(1+X)) + fmovemx %fp0-%fp0,(%a0) | ...overwrite input + movel %d1,-(%sp) |save original users fpcr + clrl %d1 + bsr satan | ...ATAN(SQRT([1-X]/[1+X])) + fmovel (%sp)+,%fpcr |restore users exceptions + faddx %fp0,%fp0 | ...2 * ATAN( STUFF ) + bra t_frcinx + +ACOSBIG: + fabsx %fp0 + fcmps #0x3F800000,%fp0 + fbgt t_operr |cause an operr exception + +|--|X| = 1, ACOS(X) = 0 OR PI + movel (%a0),%d0 | ...pack exponent with upper 16 fraction + movew 4(%a0),%d0 + cmpl #0,%d0 |D0 has original exponent+fraction + bgts ACOSP1 + +|--X = -1 +|Returns PI and inexact exception + fmovex PI,%fp0 + fmovel %d1,%FPCR + fadds #0x00800000,%fp0 |cause an inexact exception to be put +| ;into the 040 - will not trap until next +| ;fp inst. + bra t_frcinx + +ACOSP1: + fmovel %d1,%FPCR + fmoves #0x00000000,%fp0 + rts |Facos ; of +1 is exact + + |end |