Linux-2.6.12-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!
diff --git a/arch/i386/math-emu/poly_atan.c b/arch/i386/math-emu/poly_atan.c
new file mode 100644
index 0000000..82f7029
--- /dev/null
+++ b/arch/i386/math-emu/poly_atan.c
@@ -0,0 +1,229 @@
+/*---------------------------------------------------------------------------+
+ | poly_atan.c |
+ | |
+ | Compute the arctan of a FPU_REG, using a polynomial approximation. |
+ | |
+ | Copyright (C) 1992,1993,1994,1997 |
+ | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
+ | E-mail billm@suburbia.net |
+ | |
+ | |
+ +---------------------------------------------------------------------------*/
+
+#include "exception.h"
+#include "reg_constant.h"
+#include "fpu_emu.h"
+#include "fpu_system.h"
+#include "status_w.h"
+#include "control_w.h"
+#include "poly.h"
+
+
+#define HIPOWERon 6 /* odd poly, negative terms */
+static const unsigned long long oddnegterms[HIPOWERon] =
+{
+ 0x0000000000000000LL, /* Dummy (not for - 1.0) */
+ 0x015328437f756467LL,
+ 0x0005dda27b73dec6LL,
+ 0x0000226bf2bfb91aLL,
+ 0x000000ccc439c5f7LL,
+ 0x0000000355438407LL
+} ;
+
+#define HIPOWERop 6 /* odd poly, positive terms */
+static const unsigned long long oddplterms[HIPOWERop] =
+{
+/* 0xaaaaaaaaaaaaaaabLL, transferred to fixedpterm[] */
+ 0x0db55a71875c9ac2LL,
+ 0x0029fce2d67880b0LL,
+ 0x0000dfd3908b4596LL,
+ 0x00000550fd61dab4LL,
+ 0x0000001c9422b3f9LL,
+ 0x000000003e3301e1LL
+};
+
+static const unsigned long long denomterm = 0xebd9b842c5c53a0eLL;
+
+static const Xsig fixedpterm = MK_XSIG(0xaaaaaaaa, 0xaaaaaaaa, 0xaaaaaaaa);
+
+static const Xsig pi_signif = MK_XSIG(0xc90fdaa2, 0x2168c234, 0xc4c6628b);
+
+
+/*--- poly_atan() -----------------------------------------------------------+
+ | |
+ +---------------------------------------------------------------------------*/
+void poly_atan(FPU_REG *st0_ptr, u_char st0_tag,
+ FPU_REG *st1_ptr, u_char st1_tag)
+{
+ u_char transformed, inverted,
+ sign1, sign2;
+ int exponent;
+ long int dummy_exp;
+ Xsig accumulator, Numer, Denom, accumulatore, argSignif,
+ argSq, argSqSq;
+ u_char tag;
+
+ sign1 = getsign(st0_ptr);
+ sign2 = getsign(st1_ptr);
+ if ( st0_tag == TAG_Valid )
+ {
+ exponent = exponent(st0_ptr);
+ }
+ else
+ {
+ /* This gives non-compatible stack contents... */
+ FPU_to_exp16(st0_ptr, st0_ptr);
+ exponent = exponent16(st0_ptr);
+ }
+ if ( st1_tag == TAG_Valid )
+ {
+ exponent -= exponent(st1_ptr);
+ }
+ else
+ {
+ /* This gives non-compatible stack contents... */
+ FPU_to_exp16(st1_ptr, st1_ptr);
+ exponent -= exponent16(st1_ptr);
+ }
+
+ if ( (exponent < 0) || ((exponent == 0) &&
+ ((st0_ptr->sigh < st1_ptr->sigh) ||
+ ((st0_ptr->sigh == st1_ptr->sigh) &&
+ (st0_ptr->sigl < st1_ptr->sigl))) ) )
+ {
+ inverted = 1;
+ Numer.lsw = Denom.lsw = 0;
+ XSIG_LL(Numer) = significand(st0_ptr);
+ XSIG_LL(Denom) = significand(st1_ptr);
+ }
+ else
+ {
+ inverted = 0;
+ exponent = -exponent;
+ Numer.lsw = Denom.lsw = 0;
+ XSIG_LL(Numer) = significand(st1_ptr);
+ XSIG_LL(Denom) = significand(st0_ptr);
+ }
+ div_Xsig(&Numer, &Denom, &argSignif);
+ exponent += norm_Xsig(&argSignif);
+
+ if ( (exponent >= -1)
+ || ((exponent == -2) && (argSignif.msw > 0xd413ccd0)) )
+ {
+ /* The argument is greater than sqrt(2)-1 (=0.414213562...) */
+ /* Convert the argument by an identity for atan */
+ transformed = 1;
+
+ if ( exponent >= 0 )
+ {
+#ifdef PARANOID
+ if ( !( (exponent == 0) &&
+ (argSignif.lsw == 0) && (argSignif.midw == 0) &&
+ (argSignif.msw == 0x80000000) ) )
+ {
+ EXCEPTION(EX_INTERNAL|0x104); /* There must be a logic error */
+ return;
+ }
+#endif /* PARANOID */
+ argSignif.msw = 0; /* Make the transformed arg -> 0.0 */
+ }
+ else
+ {
+ Numer.lsw = Denom.lsw = argSignif.lsw;
+ XSIG_LL(Numer) = XSIG_LL(Denom) = XSIG_LL(argSignif);
+
+ if ( exponent < -1 )
+ shr_Xsig(&Numer, -1-exponent);
+ negate_Xsig(&Numer);
+
+ shr_Xsig(&Denom, -exponent);
+ Denom.msw |= 0x80000000;
+
+ div_Xsig(&Numer, &Denom, &argSignif);
+
+ exponent = -1 + norm_Xsig(&argSignif);
+ }
+ }
+ else
+ {
+ transformed = 0;
+ }
+
+ argSq.lsw = argSignif.lsw; argSq.midw = argSignif.midw;
+ argSq.msw = argSignif.msw;
+ mul_Xsig_Xsig(&argSq, &argSq);
+
+ argSqSq.lsw = argSq.lsw; argSqSq.midw = argSq.midw; argSqSq.msw = argSq.msw;
+ mul_Xsig_Xsig(&argSqSq, &argSqSq);
+
+ accumulatore.lsw = argSq.lsw;
+ XSIG_LL(accumulatore) = XSIG_LL(argSq);
+
+ shr_Xsig(&argSq, 2*(-1-exponent-1));
+ shr_Xsig(&argSqSq, 4*(-1-exponent-1));
+
+ /* Now have argSq etc with binary point at the left
+ .1xxxxxxxx */
+
+ /* Do the basic fixed point polynomial evaluation */
+ accumulator.msw = accumulator.midw = accumulator.lsw = 0;
+ polynomial_Xsig(&accumulator, &XSIG_LL(argSqSq),
+ oddplterms, HIPOWERop-1);
+ mul64_Xsig(&accumulator, &XSIG_LL(argSq));
+ negate_Xsig(&accumulator);
+ polynomial_Xsig(&accumulator, &XSIG_LL(argSqSq), oddnegterms, HIPOWERon-1);
+ negate_Xsig(&accumulator);
+ add_two_Xsig(&accumulator, &fixedpterm, &dummy_exp);
+
+ mul64_Xsig(&accumulatore, &denomterm);
+ shr_Xsig(&accumulatore, 1 + 2*(-1-exponent));
+ accumulatore.msw |= 0x80000000;
+
+ div_Xsig(&accumulator, &accumulatore, &accumulator);
+
+ mul_Xsig_Xsig(&accumulator, &argSignif);
+ mul_Xsig_Xsig(&accumulator, &argSq);
+
+ shr_Xsig(&accumulator, 3);
+ negate_Xsig(&accumulator);
+ add_Xsig_Xsig(&accumulator, &argSignif);
+
+ if ( transformed )
+ {
+ /* compute pi/4 - accumulator */
+ shr_Xsig(&accumulator, -1-exponent);
+ negate_Xsig(&accumulator);
+ add_Xsig_Xsig(&accumulator, &pi_signif);
+ exponent = -1;
+ }
+
+ if ( inverted )
+ {
+ /* compute pi/2 - accumulator */
+ shr_Xsig(&accumulator, -exponent);
+ negate_Xsig(&accumulator);
+ add_Xsig_Xsig(&accumulator, &pi_signif);
+ exponent = 0;
+ }
+
+ if ( sign1 )
+ {
+ /* compute pi - accumulator */
+ shr_Xsig(&accumulator, 1 - exponent);
+ negate_Xsig(&accumulator);
+ add_Xsig_Xsig(&accumulator, &pi_signif);
+ exponent = 1;
+ }
+
+ exponent += round_Xsig(&accumulator);
+
+ significand(st1_ptr) = XSIG_LL(accumulator);
+ setexponent16(st1_ptr, exponent);
+
+ tag = FPU_round(st1_ptr, 1, 0, FULL_PRECISION, sign2);
+ FPU_settagi(1, tag);
+
+ set_precision_flag_up(); /* We do not really know if up or down,
+ use this as the default. */
+
+}