gdb/rdi-share/tx.c

   1 /*
   2  * Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
   3  *
   4  * This software may be freely used, copied, modified, and distributed
   5  * provided that the above copyright notice is preserved in all copies of the
   6  * software.
   7  */
   8
   9 /*-*-C-*-
  10  *
  11  * $Revision$
  12  *     $Date$
  13  *
  14  *   Project: ANGEL
  15  *
  16  *     Title: Character based packet transmission engine
  17  */
  18
  19 #include <stdarg.h>    /* ANSI varargs support */
  20 #include "angel.h"     /* Angel system definitions */
  21 #include "endian.h"    /* Endian independant memory access macros */
  22 #include "crc.h"       /* crc generation definitions and headers */
  23 #include "rxtx.h"
  24 #include "channels.h"
  25 #include "buffers.h"
  26 #include "logging.h"
  27
  28 /* definitions to describe the engines state */
  29 #define N_STX           0x0  /* first 2 bits for N_ */
  30 #define N_BODY          0x1
  31 #define N_ETX           0x2
  32 #define N_IDLE          0x3
  33 #define N_MASK          0x3 /* mask for the Encapsulator state */
  34
  35 #define E_PLAIN         (0x0 << 2) /* 3rd bit for E_ */
  36 #define E_ESC           (0x1 << 2) /* 3rd bit for E_ */
  37 #define E_MASK          (0x1 << 2) /* mask for the Escaper state */
  38
  39 #define F_HEAD          (0x0 << 3) /* 4th and 5th bits for F_ */
  40 #define F_DATA          (0x1 << 3)
  41 #define F_CRC           (0x1 << 4)
  42 #define F_MASK          (0x3 << 3) /* mask for the Escaper state */
  43
  44 static unsigned char escape(unsigned char ch_in, struct te_state *txstate);
  45
  46 void Angel_TxEngineInit(const struct re_config *txconfig,
  47                         const struct data_packet *packet,
  48                         struct te_state *txstate){
  49   IGNORE(packet);
  50   txstate->tx_state = N_STX | E_PLAIN | F_HEAD;
  51   txstate->field_c = 0;
  52   txstate->encoded = 0;
  53   txstate->config = txconfig;
  54   txstate->crc = 0;
  55 }
  56
  57 te_status Angel_TxEngine(const struct data_packet *packet,
  58                          struct te_state *txstate,
  59                          unsigned char *tx_ch){
  60   /* TODO: gaurd on long/bad packets */
  61   /*
  62    * encapsulate the packet, framing has been moved from a seperate
  63    * function into the encapsulation routine as it needed too much
  64    * inherited state for it to be sensibly located elsewhere
  65    */
  66   switch ((txstate->tx_state) & N_MASK){
  67   case N_STX:
  68 #ifdef DO_TRACE
  69     __rt_trace("txe-stx ");
  70 #endif
  71     txstate->tx_state = (txstate->tx_state & ~N_MASK) | N_BODY;
  72     *tx_ch = txstate->config->stx;
  73     txstate->field_c = 3; /* set up for the header */
  74     txstate->crc = startCRC32; /* set up basic crc */
  75     return TS_IN_PKT;
  76   case N_BODY:{
  77     switch (txstate->tx_state & F_MASK) {
  78     case F_HEAD:
  79 #ifdef DO_TRACE
  80     __rt_trace("txe-head ");
  81 #endif
  82       if (txstate->field_c == 3) {
  83         /* send type */
  84         *tx_ch = escape(packet->type, txstate);
  85         return TS_IN_PKT;
  86       }
  87       else {
  88         *tx_ch = escape((packet->len >> (txstate->field_c - 1) * 8) & 0xff,
  89                       txstate);
  90           if (txstate->field_c == 0) {
  91             /* move on to the next state */
  92             txstate->tx_state = (txstate->tx_state & ~F_MASK) | F_DATA;
  93             txstate->field_c = packet->len;
  94           }
  95         return TS_IN_PKT;
  96       }
  97     case F_DATA:
  98 #ifdef DO_TRACE
  99     __rt_trace("txe-data ");
 100 #endif
 101       *tx_ch = escape(packet->data[packet->len - txstate->field_c], txstate);
 102       if (txstate->field_c == 0) {
 103         /* move on to the next state */
 104         txstate->tx_state = (txstate->tx_state & ~F_MASK) | F_CRC;
 105         txstate->field_c = 4;
 106       }
 107       return TS_IN_PKT;
 108     case F_CRC:
 109 #ifdef DO_TRACE
 110     __rt_trace("txe-crc ");
 111 #endif
 112      *tx_ch = escape((txstate->crc >> ((txstate->field_c - 1) * 8)) & 0xff,
 113                       txstate);
 114
 115       if (txstate->field_c == 0) {
 116 #ifdef DO_TRACE
 117         __rt_trace("txe crc = 0x%x\n", txstate->crc);
 118 #endif
 119         /* move on to the next state */
 120         txstate->tx_state = (txstate->tx_state & ~N_MASK) | N_ETX;
 121       }
 122       return TS_IN_PKT;
 123     }
 124   }
 125   case N_ETX:
 126 #ifdef DO_TRACE
 127     __rt_trace("txe-etx\n");
 128 #endif
 129     txstate->tx_state = (txstate->tx_state & ~N_MASK) | N_IDLE;
 130     *tx_ch = txstate->config->etx;
 131     return TS_DONE_PKT;
 132   default:
 133 #ifdef DEBUG
 134     __rt_info("tx default\n");
 135 #endif
 136     txstate->tx_state = (txstate->tx_state & ~N_MASK) | N_IDLE;
 137     return TS_IDLE;
 138   }
 139   /* stop a silly -Wall warning */
 140   return (te_status)-1;
 141 }
 142
 143 /*
 144  * crc generation occurs in the escape function because it is the only
 145  * place where we know that we're putting a real char into the buffer
 146  * rather than an escaped one.
 147  * We must be careful here not to update the crc when we're sending it
 148  */
 149 static unsigned char escape(unsigned char ch_in, struct te_state *txstate) {
 150    if (((txstate->tx_state) & E_MASK) == E_ESC) {
 151       /* char has been escaped so send the real char */
 152 #ifdef DO_TRACE
 153      __rt_trace("txe-echar ");
 154 #endif
 155       txstate->tx_state = (txstate->tx_state & ~E_MASK) | E_PLAIN;
 156       txstate->field_c--;
 157       if ((txstate->tx_state & F_MASK) != F_CRC)
 158         txstate->crc = crc32( &ch_in, 1, txstate->crc);
 159       return ch_in | serial_ESCAPE;
 160    }
 161    if ((ch_in < 32) && ((txstate->config->esc_set & (1 << ch_in)) != 0)) {
 162      /* char needs escaping */
 163 #ifdef DO_TRACE
 164      __rt_trace("txe-esc ");
 165 #endif
 166      txstate->tx_state = (txstate->tx_state & ~E_MASK) | E_ESC;
 167      return txstate->config->esc;
 168    }
 169    /* must be a char that can be sent plain */
 170    txstate->field_c--;
 171    if ((txstate->tx_state & F_MASK) != F_CRC)
 172      txstate->crc = crc32(&ch_in, 1, txstate->crc);
 173    return ch_in;
 174 }
 175
 176 /* EOF tx.c */