mirror of
https://github.com/marqs85/ossc
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134 lines
3.9 KiB
C
134 lines
3.9 KiB
C
/*
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* Copyright (c) 2003-2004 Altera Corporation, San Jose, California, USA.
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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* ------------
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*
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* Altera does not recommend, suggest or require that this reference design
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* file be used in conjunction or combination with any other product.
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*
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* alt_busy_sleep.c - Microsecond delay routine which uses a calibrated busy
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* loop to perform the delay. This is used to implement
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* usleep for both uC/OS-II and the standalone HAL.
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*
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* Author PRR
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*
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* Calibrated delay with no timer required
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*
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* The ASM instructions in the routine are equivalent to
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*
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* for (i=0;i<us*(ALT_CPU_FREQ/3);i++);
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*
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* and takes three cycles each time around the loop
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*
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*/
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#include <limits.h>
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#include <string.h>
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#include "system.h"
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#include "alt_types.h"
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#include "priv/alt_busy_sleep.h"
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unsigned int alt_busy_sleep (unsigned int us)
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{
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/*
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* Only delay if ALT_SIM_OPTIMIZE is not defined; i.e., if software
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* is built targetting ModelSim RTL simulation, the delay will be
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* skipped to speed up simulation.
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*/
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#ifndef ALT_SIM_OPTIMIZE
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int i;
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int big_loops;
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alt_u32 cycles_per_loop;
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if (!strcmp(NIOS2_CPU_IMPLEMENTATION,"tiny"))
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{
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cycles_per_loop = 9;
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}
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else
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{
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cycles_per_loop = 3;
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}
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big_loops = us / (INT_MAX/
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(ALT_CPU_FREQ/(cycles_per_loop * 1000000)));
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if (big_loops)
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{
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for(i=0;i<big_loops;i++)
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{
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/*
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* Do NOT Try to single step the asm statement below
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* (single step will never return)
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* Step out of this function or set a breakpoint after the asm statements
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*/
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__asm__ volatile (
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"\n0:"
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"\n\taddi %0,%0, -1"
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"\n\tbne %0,zero,0b"
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"\n1:"
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"\n\t.pushsection .debug_alt_sim_info"
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"\n\t.int 4, 0, 0b, 1b"
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"\n\t.popsection"
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:: "r" (INT_MAX));
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us -= (INT_MAX/(ALT_CPU_FREQ/
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(cycles_per_loop * 1000000)));
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}
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/*
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* Do NOT Try to single step the asm statement below
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* (single step will never return)
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* Step out of this function or set a breakpoint after the asm statements
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*/
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__asm__ volatile (
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"\n0:"
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"\n\taddi %0,%0, -1"
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"\n\tbne %0,zero,0b"
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"\n1:"
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"\n\t.pushsection .debug_alt_sim_info"
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"\n\t.int 4, 0, 0b, 1b"
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"\n\t.popsection"
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:: "r" (us*(ALT_CPU_FREQ/(cycles_per_loop * 1000000))));
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}
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else
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{
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/*
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* Do NOT Try to single step the asm statement below
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* (single step will never return)
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* Step out of this function or set a breakpoint after the asm statements
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*/
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__asm__ volatile (
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"\n0:"
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"\n\taddi %0,%0, -1"
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"\n\tbgt %0,zero,0b"
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"\n1:"
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"\n\t.pushsection .debug_alt_sim_info"
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"\n\t.int 4, 0, 0b, 1b"
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"\n\t.popsection"
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:: "r" (us*(ALT_CPU_FREQ/(cycles_per_loop * 1000000))));
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}
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#endif /* #ifndef ALT_SIM_OPTIMIZE */
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return 0;
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}
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