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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [gcc/] [config/] [spu/] [mfc_multi_tag_reserve.c] - Rev 327
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/* Copyright (C) 2007, 2009 Free Software Foundation, Inc. This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC 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 General Public License for more details. Under Section 7 of GPL version 3, you are granted additional permissions described in the GCC Runtime Library Exception, version 3.1, as published by the Free Software Foundation. You should have received a copy of the GNU General Public License and a copy of the GCC Runtime Library Exception along with this program; see the files COPYING3 and COPYING.RUNTIME respectively. If not, see <http://www.gnu.org/licenses/>. */ #include <spu_mfcio.h> extern vector unsigned int __mfc_tag_table; /* Reserve a sequential group of tags for exclusive use. The number of tags to be reserved is specified by the <number_of_tags> parameter. This routine returns the first tag ID for a sequential list of available tags and marks them as reserved. The reserved group of tags is in the range starting from the returned tag through the returned tag + <number_of_tags>-1. If the number of tags requested exceeds the number of available sequential tags, then MFC_DMA_TAG_INVALID is returned indicating that the request could not be serviced. */ unsigned int __mfc_multi_tag_reserve (unsigned int number_of_tags) { vector unsigned int table_copy; vector unsigned int one = (vector unsigned int) { 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; vector unsigned int count_busy, is_valid; vector unsigned int count_total; vector unsigned int count_avail = (vector unsigned int) { 0, 0, 0, 0 }; vector unsigned int index = (vector unsigned int) { 0, 0, 0, 0 }; table_copy = __mfc_tag_table; /* count_busy: number of consecutive busy tags count_avail: number of consecutive free tags table_copy: temporary copy of the tag table count_total: sum of count_busy and count_avail index: index of the current working tag */ do { table_copy = spu_sl (table_copy, count_avail); count_busy = spu_cntlz (table_copy); table_copy = spu_sl (table_copy, count_busy); count_avail = spu_cntlz (spu_xor(table_copy, -1)); count_total = spu_add (count_busy, count_avail); index = spu_add (index, count_total); } while (spu_extract (count_avail, 0) < number_of_tags && spu_extract (table_copy, 0) != 0); index = spu_sub (index, count_avail); /* is_valid is set to 0xFFFFFFFF if table_copy == 0, 0 otherwise. */ is_valid = spu_cmpeq (table_copy, 0); index = spu_sel (index, is_valid, is_valid); /* Now I need to actually mark the tags as used. */ table_copy = spu_sl (one, number_of_tags); table_copy = spu_rl (table_copy, -number_of_tags - spu_extract (index, 0)); table_copy = spu_sel (table_copy, __mfc_tag_table, table_copy); __mfc_tag_table = spu_sel (table_copy, __mfc_tag_table, is_valid); return spu_extract (index, 0); }
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