src/libm/s_floor.c
author Ryan C. Gordon <icculus@icculus.org>
Thu, 09 Apr 2015 22:28:37 -0400
changeset 9541 cf8fab52e33b
parent 6044 35448a5ea044
child 11683 48bcba563d9c
permissions -rw-r--r--
Merged Alex Szpakowski's iOS-improvement branch to default.

Fixes Bugzilla #2798.
Fixes Bugzilla #2212.
Fixes Bugzilla #2826.
Fixes Bugzilla #2661.
Fixes Bugzilla #1885.
Fixes Bugzilla #1578.
Fixes Bugzilla #2751.

(whew!)

Notable changes, from Alex's notes:

- The SDL_WINDOW_ALLOW_HIGHDPI flag is now needed (along with SDL_GL_GetDrawableSize or SDL_GetRendererOutputSize) to use Retina / high DPI resolutions, bringing SDL’s Retina-related behavior on iOS in line with Mac OS X. Window dimensions and display modes are now in the “points” (non-high DPI) coordinate system rather than pixels, whereas SDL_GL_GetDrawableSize is in pixels.

- Reworked the custom extended launch screen code:
- It now hides after the first SDL_PumpEvents call rather than SDL_CreateWindow, and it fades out in a similar manner to the system launch screen behavior.
- It now mirrors the system launch screen behavior when deciding which image to display: it falls back to using the Launch Images dictionary in Info.plist if the iOS 8+ launch screen nib isn’t available, and if the Launch Images dictionary doesn’t exist it uses the old standard launch image names.
- The extended launch screen can now be disabled via the SDL_IPHONE_LAUNCHSCREEN define in SDL_config_iphoneos.h.

- Added support for SDL_HINT_ACCELEROMETER_AS_JOYSTICK.

- Added access to a window view's renderbuffer and framebuffer to syswm.

- Added OpenGL ES debug labels for the Renderbuffer and Framebuffer Objects created with SDL_GL_CreateContext.

- Added support for sRGB OpenGL ES contexts on iOS 7+.

- Updated OpenGL ES contexts to support native-resolution rendering (when SDL_WINDOW_ALLOW_HIGHDPI is enabled) on the iPhone 6 Plus, i.e. 1080x1920 rather than 1242x2208.

- Updated SDL_GL_CreateContext, SDL_GL_SwapWindow, SDL_GL_MakeCurrent, and SDL_GL_DeleteContext to be more robust.

- Updated SDL windows to display a UIView at all times, even when an OpenGL context is not active. This allows rotation, touch events, and other windowing-related events to work properly without an active OpenGL context. It also makes it easier to use SDL_GetWindowWMInfo after creating a SDL window.

- Updated the iOS-specific Objective-C code to use cleaner and more modern language features and APIs, including ARC instead of manual reference counting.

- Updated SDL_HINT_ORIENTATIONS to allow disabling custom orientations if the hint is set with no valid orientation names.

- Fixed several rotation and orientation bugs with windows and display modes, especially in iOS 8+.

- Fixed SDL_SetWindowFullscreen failing to update the status bar visibility on iOS 7+.

- Fixed the orientation of the offset applied to the window’s view when the onscreen keyboard is shown in iOS 8+.

- Fixed SDL_IsScreenKeyboardShown (patch by Phil Hassey.)

- Fixed several major memory leaks caused by missing autorelease pool blocks in the iOS-specific Objective-C code.

- Removed several dead code paths.

- The iOS 7 SDK (Xcode 5) or newer is now required to build SDL for iOS.
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/* @(#)s_floor.c 5.1 93/09/24 */
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/*
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 * ====================================================
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 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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 *
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 * Developed at SunPro, a Sun Microsystems, Inc. business.
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 * Permission to use, copy, modify, and distribute this
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 * software is freely granted, provided that this notice
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 * is preserved.
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 * ====================================================
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 */
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#if defined(LIBM_SCCS) && !defined(lint)
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static const char rcsid[] =
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    "$NetBSD: s_floor.c,v 1.8 1995/05/10 20:47:20 jtc Exp $";
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#endif
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/*
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 * floor(x)
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 * Return x rounded toward -inf to integral value
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 * Method:
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 *	Bit twiddling.
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 * Exception:
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 *	Inexact flag raised if x not equal to floor(x).
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 */
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#include "math_libm.h"
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#include "math_private.h"
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#ifdef __STDC__
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static const double huge_val = 1.0e300;
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#else
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static double huge_val = 1.0e300;
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#endif
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libm_hidden_proto(floor)
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#ifdef __STDC__
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     double floor(double x)
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#else
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     double floor(x)
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     double x;
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#endif
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{
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    int32_t i0, i1, j0;
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    u_int32_t i, j;
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    EXTRACT_WORDS(i0, i1, x);
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    j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
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    if (j0 < 20) {
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        if (j0 < 0) {           /* raise inexact if x != 0 */
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            if (huge_val + x > 0.0) {       /* return 0*sign(x) if |x|<1 */
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                if (i0 >= 0) {
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                    i0 = i1 = 0;
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                } else if (((i0 & 0x7fffffff) | i1) != 0) {
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                    i0 = 0xbff00000;
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                    i1 = 0;
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                }
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            }
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        } else {
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            i = (0x000fffff) >> j0;
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            if (((i0 & i) | i1) == 0)
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                return x;       /* x is integral */
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            if (huge_val + x > 0.0) {       /* raise inexact flag */
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                if (i0 < 0)
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                    i0 += (0x00100000) >> j0;
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                i0 &= (~i);
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                i1 = 0;
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            }
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        }
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    } else if (j0 > 51) {
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        if (j0 == 0x400)
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            return x + x;       /* inf or NaN */
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        else
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            return x;           /* x is integral */
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    } else {
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        i = ((u_int32_t) (0xffffffff)) >> (j0 - 20);
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        if ((i1 & i) == 0)
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            return x;           /* x is integral */
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        if (huge_val + x > 0.0) {   /* raise inexact flag */
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            if (i0 < 0) {
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                if (j0 == 20)
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                    i0 += 1;
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                else {
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                    j = i1 + (1 << (52 - j0));
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                    if (j < (u_int32_t) i1)
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                        i0 += 1;        /* got a carry */
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                    i1 = j;
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                }
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            }
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            i1 &= (~i);
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        }
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    }
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    INSERT_WORDS(x, i0, i1);
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    return x;
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}
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libm_hidden_def(floor)