| /* |
| Simple DirectMedia Layer |
| Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org> |
| |
| This software is provided 'as-is', without any express or implied |
| warranty. In no event will the authors be held liable for any damages |
| arising from the use of this software. |
| |
| Permission is granted to anyone to use this software for any purpose, |
| including commercial applications, and to alter it and redistribute it |
| freely, subject to the following restrictions: |
| |
| 1. The origin of this software must not be misrepresented; you must not |
| claim that you wrote the original software. If you use this software |
| in a product, an acknowledgment in the product documentation would be |
| appreciated but is not required. |
| 2. Altered source versions must be plainly marked as such, and must not be |
| misrepresented as being the original software. |
| 3. This notice may not be removed or altered from any source distribution. |
| */ |
| |
| #include "../SDL_internal.h" |
| |
| /* This file contains a portable memset manipulation function for SDL */ |
| |
| void * |
| SDL_memset(SDL_OUT_BYTECAP(len) void *dst, int c, size_t len) |
| { |
| #if defined(HAVE_MEMSET) |
| return memset(dst, c, len); |
| #else |
| size_t left; |
| Uint32 *dstp4; |
| Uint8 *dstp1 = (Uint8 *) dst; |
| Uint8 value1; |
| Uint32 value4; |
| |
| /* The value used in memset() is a byte, passed as an int */ |
| c &= 0xff; |
| |
| /* The destination pointer needs to be aligned on a 4-byte boundary to |
| * execute a 32-bit set. Set first bytes manually if needed until it is |
| * aligned. */ |
| value1 = (Uint8)c; |
| while ((uintptr_t)dstp1 & 0x3) { |
| if (len--) { |
| *dstp1++ = value1; |
| } else { |
| return dst; |
| } |
| } |
| |
| value4 = ((Uint32)c | ((Uint32)c << 8) | ((Uint32)c << 16) | ((Uint32)c << 24)); |
| dstp4 = (Uint32 *) dstp1; |
| left = (len % 4); |
| len /= 4; |
| while (len--) { |
| *dstp4++ = value4; |
| } |
| |
| dstp1 = (Uint8 *) dstp4; |
| switch (left) { |
| case 3: |
| *dstp1++ = value1; |
| case 2: |
| *dstp1++ = value1; |
| case 1: |
| *dstp1++ = value1; |
| } |
| |
| return dst; |
| #endif /* HAVE_MEMSET */ |
| } |
| |
| /* vi: set ts=4 sw=4 expandtab: */ |