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  • Committer: Bazaar Package Importer
  • Author(s): Hakan Ardo
  • Date: 2006-05-01 12:03:39 UTC
  • mto: (3.1.1 edgy)
  • mto: This revision was merged to the branch mainline in revision 4.
  • Revision ID: james.westby@ubuntu.com-20060501120339-q93dxulpunby36dj
Tags: upstream-1.4.4
Import upstream version 1.4.4

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libm/fplib/tan.S
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   POSSIBILITY OF SUCH DAMAGE. 
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*/
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/* $Id: tan.S,v 1.7.2.1 2005/12/11 19:40:01 aesok Exp $ */
 
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/*
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    tan.S is part of     FPlib V 0.3.0       ported to avr-as
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    for details see readme.fplib
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 * the formula tan(x) = 1/tan(PI/2 - x) is used for values > PI/4
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 */
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#if !defined(DOXYGEN)
 
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#if !defined(__DOXYGEN__)
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#include "gasava.inc"
 
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#include "macros.inc"
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#include "fplib.inc"
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          TEXT_SEG(fplib, tan)
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       ANDI    rSI0,0x80        ; assume inversion flag zero
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       ANDI    rA3,0x7F
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       CPI     rA3,0x39
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       BRCS    _tan_100         ; (tan(A < 0x39000000)=A)
 
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       BRCS    100f             ; (tan(A < 0x39000000)=A)
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       LDI     rB3,0x40
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       LDI     rB2,0x49
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       CPC     rB1,rA1
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       CPC     rB2,rA2
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       CPC     rB3,rA3          ; B(=PI/2) - A
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       BREQ    _tan_INF
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       BRCC    _tan_10
 
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       BREQ    101f
 
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       BRCC    1f
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       LDI     rB3,0x40
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       LDI     rB2,0x49         ; load PI
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       ORI     rA3,0x80         ; A = -A
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       RCALL   _U(__addsf3)     ; A = A+B = B + (-A)
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       LDI     rB3,0x80
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       EOR     rSI0,rB3
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 _tan_10:
 
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1:
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       LDI     rB3,0x3F
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       LDI     rB2,0x49
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       LDI     rB1,0x0F
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       CPC     rB1,rA1
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       CPC     rB2,rA2
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       CPC     rB3,rA3          ; B(=PI/4) - A
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       BRCC    _tan_00
 
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       BRCC    1f
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       INC     rSI0
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       ORI     rA3,0x80         ; negate A
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       LDI     rB2,0xC9         ; P/4 -> PI/2
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       RCALL   _U(__addsf3)     ; PI/2 - A
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 _tan_00:
 
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       PUSH    rA3
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       PUSH    rA2
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       PUSH    rA1
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       POP     rB3
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       RCALL   _U(__mulsf3)
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       SBRS    rSI0,0
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       RJMP    _tan_100
 
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       RJMP    100f
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       RCALL   _U(__fp_inverse)
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 _tan_100:
 
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100:
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       SBRC    rSI0,7
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       ORI     rA3,0x80
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       POP     rSI0
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       RET
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 _tan_INF:
 
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       POP     rSI0
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       RJMP    _U(__fp_nan)
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 * h3  : 0.000253971
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 * h2  : 0.0245202
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 * h1  : 0.464239
 
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 * 1.0
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 */
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        PGM_SECTION
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        /* these constants are *no* IEEE float values:  exponent unpacked allready
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         *                                              first byte : exponent
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         *                                              2nd byte   : msb of mantissa with sign as bit 7
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         *                                              3rd & 4th byte : mantissa
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         */
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 table_tan:  DCB 3 ; no of table entries - 1 (preload value)
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             DCB 0x73, 0x05, 0x27, 0x60     ; h - first calculate denominator
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             DCB 0x79, 0x48, 0xDE, 0x92
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             DCB 0x7D, 0x6D, 0xB0, 0xCA
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             DCB 0x7F, 0x00, 0x00, 0x00
 
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table_tan:  DCB 3 ; no of table entries - 1 (preload value)
 
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             DCB 0x39, 0x85, 0x27, 0x60     ; h - first calculate denominator
 
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             DCB 0x3C, 0xC8, 0xDE, 0x92
 
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             DCB 0x3E, 0xED, 0xB0, 0xCA
 
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             DCB 0x3F, 0x80, 0x00, 0x00
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             DCB 3 ; no of table entries - 1 (preload value)
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             DCB 0x6E, 0x37, 0x00, 0xF3     ; f
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             DCB 0x76, 0x4B, 0x9F, 0xB8
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             DCB 0x7C, 0x06, 0x0C, 0x3E
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             DCB 0x7F, 0x00, 0x00, 0x00
 
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             DCB 0x37, 0x37, 0x00, 0xF3     ; f
 
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             DCB 0x3B, 0x4B, 0x9F, 0xB8
 
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             DCB 0x3E, 0x06, 0x0C, 0x3E
 
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             DCB 0x3F, 0x80, 0x00, 0x00
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#endif /* not DOXYGEN */
 
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#endif /* not __DOXYGEN__ */