24 lines
582 B
NASM
24 lines
582 B
NASM
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format ELF
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include '../proc32.inc'
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section '.text' executable
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public acos_ as "acos"
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acos_:
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; acos(x) = atan(sqrt((1-x*x)/(x*x)))
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fld qword[esp+4]
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fld st0 ;Duplicate X on tos.
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fmul st0, st1 ;Compute X**2.
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fld st0 ;Duplicate X**2 on tos.
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fld1 ;Compute 1-X**2.
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fsub st0, st1
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fdiv st0, st1 ;Compute (1-x**2)/X**2.
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fsqrt ;Compute sqrt((1-X**2)/X**2).
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fld1 ;To compute full arctangent.
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fpatan ;Compute atan of the above.
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ret
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