URL
https://opencores.org/ocsvn/ao486/ao486/trunk
Subversion Repositories ao486
[/] [ao486/] [trunk/] [syn/] [soc/] [firmware/] [exe_bsp/] [HAL/] [src/] [alt_busy_sleep.c] - Rev 2
Compare with Previous | Blame | View Log
/* * Copyright (c) 2003-2004 Altera Corporation, San Jose, California, USA. * All rights reserved. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to * deal in the Software without restriction, including without limitation the * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or * sell copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. * * ------------ * * Altera does not recommend, suggest or require that this reference design * file be used in conjunction or combination with any other product. * * alt_busy_sleep.c - Microsecond delay routine which uses a calibrated busy * loop to perform the delay. This is used to implement * usleep for both uC/OS-II and the standalone HAL. * * Author PRR * * Calibrated delay with no timer required * * The ASM instructions in the routine are equivalent to * * for (i=0;i<us*(ALT_CPU_FREQ/3);i++); * * and takes three cycles each time around the loop * */ #include <limits.h> #include <string.h> #include "system.h" #include "alt_types.h" #include "priv/alt_busy_sleep.h" unsigned int alt_busy_sleep (unsigned int us) { /* * Only delay if ALT_SIM_OPTIMIZE is not defined; i.e., if software * is built targetting ModelSim RTL simulation, the delay will be * skipped to speed up simulation. */ #ifndef ALT_SIM_OPTIMIZE int i; int big_loops; alt_u32 cycles_per_loop; if (!strcmp(NIOS2_CPU_IMPLEMENTATION,"tiny")) { cycles_per_loop = 9; } else { cycles_per_loop = 3; } big_loops = us / (INT_MAX/ (ALT_CPU_FREQ/(cycles_per_loop * 1000000))); if (big_loops) { for(i=0;i<big_loops;i++) { /* * Do NOT Try to single step the asm statement below * (single step will never return) * Step out of this function or set a breakpoint after the asm statements */ __asm__ volatile ( "\n0:" "\n\taddi %0,%0, -1" "\n\tbne %0,zero,0b" "\n1:" "\n\t.pushsection .debug_alt_sim_info" "\n\t.int 4, 0, 0b, 1b" "\n\t.popsection" :: "r" (INT_MAX)); us -= (INT_MAX/(ALT_CPU_FREQ/ (cycles_per_loop * 1000000))); } /* * Do NOT Try to single step the asm statement below * (single step will never return) * Step out of this function or set a breakpoint after the asm statements */ __asm__ volatile ( "\n0:" "\n\taddi %0,%0, -1" "\n\tbne %0,zero,0b" "\n1:" "\n\t.pushsection .debug_alt_sim_info" "\n\t.int 4, 0, 0b, 1b" "\n\t.popsection" :: "r" (us*(ALT_CPU_FREQ/(cycles_per_loop * 1000000)))); } else { /* * Do NOT Try to single step the asm statement below * (single step will never return) * Step out of this function or set a breakpoint after the asm statements */ __asm__ volatile ( "\n0:" "\n\taddi %0,%0, -1" "\n\tbgt %0,zero,0b" "\n1:" "\n\t.pushsection .debug_alt_sim_info" "\n\t.int 4, 0, 0b, 1b" "\n\t.popsection" :: "r" (us*(ALT_CPU_FREQ/(cycles_per_loop * 1000000)))); } #endif /* #ifndef ALT_SIM_OPTIMIZE */ return 0; }