diff options
Diffstat (limited to 'arch/i386/math-emu/poly_tan.c')
| -rw-r--r-- | arch/i386/math-emu/poly_tan.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/i386/math-emu/poly_tan.c b/arch/i386/math-emu/poly_tan.c index 1743d6f0f..13a32b9fc 100644 --- a/arch/i386/math-emu/poly_tan.c +++ b/arch/i386/math-emu/poly_tan.c @@ -3,9 +3,9 @@ | | | Compute the tan of a FPU_REG, using a polynomial approximation. | | | - | Copyright (C) 1992,1993,1994,1997 | + | Copyright (C) 1992,1993,1994,1997,1999 | | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | - | Australia. E-mail billm@suburbia.net | + | Australia. E-mail billm@melbpc.org.au | | | | | +---------------------------------------------------------------------------*/ @@ -84,6 +84,14 @@ void poly_tan(FPU_REG *st0_ptr) } /* pi/2 in hex is: 1.921fb54442d18469 898CC51701B839A2 52049C1 */ XSIG_LL(accum) = 0x921fb54442d18469LL - XSIG_LL(accum); + /* This is a special case which arises due to rounding. */ + if ( XSIG_LL(accum) == 0xffffffffffffffffLL ) + { + FPU_settag0(TAG_Valid); + significand(st0_ptr) = 0x8a51e04daabda360LL; + setexponent16(st0_ptr, 0x41 + EXTENDED_Ebias | SIGN_Negative); + return; + } argSignif.lsw = accum.lsw; XSIG_LL(argSignif) = XSIG_LL(accum); @@ -177,11 +185,11 @@ void poly_tan(FPU_REG *st0_ptr) else if ( exponent > -30 ) { adj = accum.msw >> -(exponent+1); /* tan */ - mul_32_32(adj, adj, &adj); /* tan^2 */ + adj = mul_32_32(adj, adj); /* tan^2 */ } else adj = 0; - mul_32_32(0x898cc517, adj, &adj); /* delta * tan^2 */ + adj = mul_32_32(0x898cc517, adj); /* delta * tan^2 */ fix_up.msw += adj; if ( !(fix_up.msw & 0x80000000) ) /* did fix_up overflow ? */ |