diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/generic/memcpy.c | 13 | ||||
| -rw-r--r-- | sysdeps/generic/memmove.c | 8 | ||||
| -rw-r--r-- | sysdeps/generic/pagecopy.h | 74 | ||||
| -rw-r--r-- | sysdeps/mach/pagecopy.h | 36 |
4 files changed, 126 insertions, 5 deletions
diff --git a/sysdeps/generic/memcpy.c b/sysdeps/generic/memcpy.c index 222d358224..e1a1ade057 100644 --- a/sysdeps/generic/memcpy.c +++ b/sysdeps/generic/memcpy.c @@ -21,6 +21,7 @@ Cambridge, MA 02139, USA. */ #include <ansidecl.h> #include <string.h> #include <memcopy.h> +#include <pagecopy.h> PTR DEFUN(memcpy, (dstpp, srcpp, len), @@ -38,10 +39,14 @@ DEFUN(memcpy, (dstpp, srcpp, len), len -= (-dstp) % OPSIZ; BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ); - /* Copy from SRCP to DSTP taking advantage of the known - alignment of DSTP. Number of bytes remaining is put - in the third argumnet, i.e. in LEN. This number may - vary from machine to machine. */ + /* Copy whole pages from SRCP to DSTP by virtual address manipulation, + as much as possible. */ + + PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len); + + /* Copy from SRCP to DSTP taking advantage of the known alignment of + DSTP. Number of bytes remaining is put in the third argument, + i.e. in LEN. This number may vary from machine to machine. */ WORD_COPY_FWD (dstp, srcp, len, len); diff --git a/sysdeps/generic/memmove.c b/sysdeps/generic/memmove.c index e3016819d9..8ef6f04cbe 100644 --- a/sysdeps/generic/memmove.c +++ b/sysdeps/generic/memmove.c @@ -1,6 +1,6 @@ /* memmove -- copy memory to memory until the specified number of bytes has been copied. Overlap is handled correctly. - Copyright (C) 1991 Free Software Foundation, Inc. + Copyright (C) 1991, 1995 Free Software Foundation, Inc. Contributed by Torbjorn Granlund (tege@sics.se). The GNU C Library is free software; you can redistribute it and/or @@ -21,6 +21,7 @@ Cambridge, MA 02139, USA. */ #include <ansidecl.h> #include <string.h> #include <memcopy.h> +#include <pagecopy.h> /* All this is so that bcopy.c can #include this file after defining some things. */ @@ -55,6 +56,11 @@ DEFUN(memmove, (a1, a2, len), len -= (-dstp) % OPSIZ; BYTE_COPY_FWD (dstp, srcp, (-dstp) % OPSIZ); + /* Copy whole pages from SRCP to DSTP by virtual address + manipulation, as much as possible. */ + + PAGE_COPY_FWD_MAYBE (dstp, srcp, len, len); + /* Copy from SRCP to DSTP taking advantage of the known alignment of DSTP. Number of bytes remaining is put in the third argumnet, i.e. in LEN. This number may diff --git a/sysdeps/generic/pagecopy.h b/sysdeps/generic/pagecopy.h new file mode 100644 index 0000000000..07202a3119 --- /dev/null +++ b/sysdeps/generic/pagecopy.h @@ -0,0 +1,74 @@ +/* Macros for copying by pages; used in memcpy, memmove. Generic macros. +Copyright (C) 1995 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +/* This file defines the macro: + + PAGE_COPY_FWD_MAYBE (dstp, srcp, nbytes_left, nbytes) + + which is invoked like WORD_COPY_FWD et al. The pointers should be at + least word aligned. This will check if virtual copying by pages can and + should be done and do it if so. + + System-specific pagecopy.h files should define these macros and then + #include this file: + + PAGE_COPY_THRESHOLD + -- Minimum size for which virtual copying by pages is worthwhile. + + PAGE_SIZE + -- Size of a page. + + PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes) + -- Macro to perform the virtual copy operation. + The pointers will be aligned to PAGE_SIZE bytes. +*/ + + +#if PAGE_COPY_THRESHOLD + +#define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes) \ + do \ + { \ + if ((nbytes) >= PAGE_COPY_THRESHOLD && \ + PAGE_OFFSET (dstp) == PAGE_OFFSET (srcp)) \ + { \ + /* The amount to copy is past the threshold for copying \ + pages virtually with kernel VM operations, and the \ + source and destination addresses have the same alignment. */ \ + size_t nbytes_before = PAGE_OFFSET (PAGE_SIZE - PAGE_OFFSET (dstp));\ + if (nbytes_before != 0) \ + { \ + /* First copy the words before the first page boundary. */ \ + WORD_COPY_FWD (dstp, srcp, nbytes_left, nbytes_before); \ + nbytes_before -= nbytes_left; \ + nbytes -= nbytes_before; \ + } \ + if (nbytes_before == 0) \ + PAGE_COPY_FWD (dstp, srcp, nbytes_left, nbytes); \ + } \ + } while (0) + +/* The page size is always a power of two, so we can avoid modulo division. */ +#define PAGE_OFFSET(n) ((n) & (PAGE_SIZE - 1)) + +#else + +#define PAGE_COPY_FWD_MAYBE(dstp, srcp, nbytes_left, nbytes) /* nada */ + +#endif diff --git a/sysdeps/mach/pagecopy.h b/sysdeps/mach/pagecopy.h new file mode 100644 index 0000000000..e75c064f06 --- /dev/null +++ b/sysdeps/mach/pagecopy.h @@ -0,0 +1,36 @@ +/* Macros for copying by pages; used in memcpy, memmove. Mach version. +Copyright (C) 1995 Free Software Foundation, Inc. +This file is part of the GNU C Library. + +The GNU C Library is free software; you can redistribute it and/or +modify it under the terms of the GNU Library General Public License as +published by the Free Software Foundation; either version 2 of the +License, or (at your option) any later version. + +The GNU C Library is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +Library General Public License for more details. + +You should have received a copy of the GNU Library General Public +License along with the GNU C Library; see the file COPYING.LIB. If +not, write to the Free Software Foundation, Inc., 675 Mass Ave, +Cambridge, MA 02139, USA. */ + +#include <mach.h> + +/* Threshold at which vm_copy is more efficient than well-optimized copying + by words. This parameter should be tuned as necessary. */ +#define PAGE_THRESHOLD (2 * PAGE_SIZE) /* XXX ? */ + +#define PAGE_SIZE __vm_page_size +#define PAGE_COPY_FWD(dstp, srcp, nbytes_left, nbytes) \ + ((nbytes_left) = ((nbytes) - \ + (__vm_copy (__mach_task_self (), \ + (vm_address_t) srcp, trunc_page (nbytes), \ + (vm_address_t) dstp) == KERN_SUCCESS \ + ? trunc_page (nbytes) \ + : 0))) + +/* Get the generic macro. */ +#include_next <pagecopy.h> |