lenval.h

00001 /*******************************************************/
00002 /* file: lenval.h                                      */
00003 /* abstract:  This file contains a description of the  */
00004 /*            data structure "lenval".                 */
00005 /*******************************************************/
00006 
00007 #ifndef lenval_dot_h
00008 #define lenval_dot_h
00009 
00010 /* the lenVal structure is a byte oriented type used to store an */
00011 /* arbitrary length binary value. As an example, the hex value   */
00012 /* 0x0e3d is represented as a lenVal with len=2 (since 2 bytes   */
00013 /* and val[0]=0e and val[1]=3d.  val[2-MAX_LEN] are undefined    */
00014 
00015 /* maximum length (in bytes) of value to read in        */
00016 /* this needs to be at least 4, and longer than the     */
00017 /* length of the longest SDR instruction.  If there is, */
00018 /* only 1 device in the chain, MAX_LEN must be at least */
00019 /* ceil(27/8) == 4.  For 6 devices in a chain, MAX_LEN  */
00020 /* must be 5, for 14 devices MAX_LEN must be 6, for 20  */
00021 /* devices MAX_LEN must be 7, etc..                     */
00022 /* You can safely set MAX_LEN to a smaller number if you*/
00023 /* know how many devices will be in your chain.         */
00024 /*  #define MAX_LEN (Actual #define is below this comment block)
00025       This #define defines the maximum length (in bytes) of predefined
00026       buffers in which the XSVF player stores the current shift data.
00027       This length must be greater than the longest shift length (in bytes)
00028       in the XSVF files that will be processed.  7000 is a very conservative
00029       number.  The buffers are stored on the stack and if you have limited
00030       stack space, you may decrease the MAX_LEN value.
00031 
00032       How to find the "shift length" in bits?
00033       Look at the ASCII version of the XSVF (generated with the -a option
00034       for the SVF2XSVF translator) and search for the XSDRSIZE command
00035       with the biggest parameter.  XSDRSIZE is equivalent to the SVF's
00036       SDR length plus the lengths of applicable HDR and TDR commands.
00037       Remember that the MAX_LEN is defined in bytes.  Therefore, the
00038       minimum MAX_LEN = ceil( max( XSDRSIZE ) / 8 );
00039 
00040       The following MAX_LEN values have been tested and provide relatively
00041       good margin for the corresponding devices:
00042 
00043         DEVICE       MAX_LEN   Resulting Shift Length Max (in bits)
00044         ---------    -------   ----------------------------------------------
00045         XC9500/XL/XV 32        256
00046 
00047         CoolRunner/II 256      2048   - actual max 1 device = 1035 bits
00048 
00049         FPGA         128       1024    - svf2xsvf -rlen 1024
00050 
00051         XC18V00/XCF00
00052                      1100      8800   - no blank check performed (default)
00053                                       - actual max 1 device = 8192 bits verify
00054                                       - max 1 device = 4096 bits program-only
00055 
00056         XC18V00/XCF00 when using the optional Blank Check operation
00057                      2500      20000  - required for blank check
00058                                       - blank check max 1 device = 16384 bits
00059 */
00060 // #define MAX_LEN 7000 /* This is the default value. But it's huge for mbed. */
00061 #define MAX_LEN 2048 /* Modified for mbed. */
00062 
00063 
00064 typedef struct var_len_byte
00065 {
00066     short len;   /* number of chars in this value */
00067     unsigned char val[MAX_LEN+1];  /* bytes of data */
00068 } lenVal;
00069 
00070 
00071 /* return the long representation of a lenVal */
00072 extern long value(lenVal *x);
00073 
00074 /* set lenVal equal to value */
00075 extern void initLenVal(lenVal *x, long value);
00076 
00077 /* check if expected equals actual (taking the mask into account) */
00078 extern short EqualLenVal(lenVal *expected, lenVal *actual, lenVal *mask);
00079 
00080 /* add val1+val2 and put the result in resVal */
00081 extern void addVal(lenVal *resVal, lenVal *val1, lenVal *val2);
00082 
00083 /* return the (byte, bit) of lv (reading from left to right) */
00084 extern short RetBit(lenVal *lv, int byte, int bit);
00085 
00086 /* set the (byte, bit) of lv equal to val (e.g. SetBit("00000000",byte, 1)
00087    equals "01000000" */
00088 extern void SetBit(lenVal *lv, int byte, int bit, short val);
00089 
00090 /* read from XSVF numBytes bytes of data into x */
00091 extern void  readVal(lenVal *x, short numBytes);
00092 
00093 #endif
00094