hw/fifo.c

   1 /*
   2  * Generic FIFO component, implemented as a circular buffer.
   3  *
   4  * Copyright (c) 2012 Peter A. G. Crosthwaite
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  *
  11  * You should have received a copy of the GNU General Public License along
  12  * with this program; if not, see <http://www.gnu.org/licenses/>.
  13  */
  14
  15 #include "fifo.h"
  16
  17 void fifo8_create(Fifo8 *fifo, uint32_t capacity)
  18 {
  19     fifo->data = g_new(uint8_t, capacity);
  20     fifo->capacity = capacity;
  21     fifo->head = 0;
  22     fifo->num = 0;
  23 }
  24
  25 void fifo8_destroy(Fifo8 *fifo)
  26 {
  27     g_free(fifo->data);
  28 }
  29
  30 void fifo8_push(Fifo8 *fifo, uint8_t data)
  31 {
  32     if (fifo->num == fifo->capacity) {
  33         abort();
  34     }
  35     fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data;
  36     fifo->num++;
  37 }
  38
  39 uint8_t fifo8_pop(Fifo8 *fifo)
  40 {
  41     uint8_t ret;
  42
  43     if (fifo->num == 0) {
  44         abort();
  45     }
  46     ret = fifo->data[fifo->head++];
  47     fifo->head %= fifo->capacity;
  48     fifo->num--;
  49     return ret;
  50 }
  51
  52 void fifo8_reset(Fifo8 *fifo)
  53 {
  54     fifo->num = 0;
  55 }
  56
  57 bool fifo8_is_empty(Fifo8 *fifo)
  58 {
  59     return (fifo->num == 0);
  60 }
  61
  62 bool fifo8_is_full(Fifo8 *fifo)
  63 {
  64     return (fifo->num == fifo->capacity);
  65 }
  66
  67 const VMStateDescription vmstate_fifo8 = {
  68     .name = "Fifo8",
  69     .version_id = 1,
  70     .minimum_version_id = 1,
  71     .minimum_version_id_old = 1,
  72     .fields      = (VMStateField[]) {
  73         VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, 0, capacity),
  74         VMSTATE_UINT32(head, Fifo8),
  75         VMSTATE_UINT32(num, Fifo8),
  76         VMSTATE_END_OF_LIST()
  77     }
  78 };