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https://github.com/lowRISC/ibex.git
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76f6a3d4c3
Move Xilinx specific code into shared folder so it can be re-used by different examples. Use the shared RAM code and make use of byte enable signal. Fixes lowrisc/ibex#144
47 lines
1.2 KiB
C
47 lines
1.2 KiB
C
// Copyright lowRISC contributors.
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// Licensed under the Apache License, Version 2.0, see LICENSE for details.
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// SPDX-License-Identifier: Apache-2.0
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#include <stdint.h>
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#define CLK_FIXED_FREQ_HZ (50ULL * 1000 * 1000)
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/**
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* Delay loop executing within 8 cycles on ibex
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*/
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static void delay_loop_ibex(unsigned long loops) {
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int out; /* only to notify compiler of modifications to |loops| */
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asm volatile(
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"1: nop \n" // 1 cycle
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" nop \n" // 1 cycle
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" nop \n" // 1 cycle
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" nop \n" // 1 cycle
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" addi %1, %1, -1 \n" // 1 cycle
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" bnez %1, 1b \n" // 3 cycles
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: "=&r" (out)
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: "0" (loops)
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);
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}
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static int usleep_ibex(unsigned long usec) {
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unsigned long usec_cycles;
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usec_cycles = CLK_FIXED_FREQ_HZ * usec / 1000 / 1000 / 8;
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delay_loop_ibex(usec_cycles);
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return 0;
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}
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static int usleep(unsigned long usec) {
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return usleep_ibex(usec);
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}
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int main(int argc, char **argv) {
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// The lowest four bits of the highest byte written to the memory region named
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// "stack" are connected to the LEDs of the board.
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volatile uint8_t *var = (volatile uint8_t *) 0x0000c010;
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*var = 0x0a;
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while (1) {
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usleep(1000 * 1000); // 1000 ms
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*var = ~(*var);
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}
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}
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