expr_width.h File Reference

This file contains a macro that is used to compute the bit-width of the result of two sub-expressions based on different combination modes. The bit-width rules for ACT expressions fall into one of the modes specified in this file. More...

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Macros
#define	WIDTH_MAX   0
	set width to the max of lw, rw
#define	WIDTH_MAX1   1
	set width to max of lw, rw + 1
#define	WIDTH_SUM   2
	set width to sum of lw, rw
#define	WIDTH_BOOL   3
	set width to 1
#define	WIDTH_LEFT   4
	set width to lw
#define	WIDTH_RIGHT   5
	set width to rw
#define	WIDTH_LSHIFT   6
	set width to lw + 2^rw-1
#define	MAX(a, b)   ((a) < (b) ? (b) : (a))
#define	WIDTH_UPDATE(mode)

Detailed Description

This file contains a macro that is used to compute the bit-width of the result of two sub-expressions based on different combination modes. The bit-width rules for ACT expressions fall into one of the modes specified in this file.

Modes: 0 = max of lw. rw 1 = max of lw, rw + 1 2 = sum of lw, rw 3 = 1 (bool result) 4 = lw itself 5 = rw itself 6 = lw + (2^rw-1)

Macro Definition Documentation

MAX

#define MAX	(		a,
			b
	)		((a) < (b) ? (b) : (a))

WIDTH_BOOL

#define WIDTH_BOOL   3

set width to 1

WIDTH_LEFT

#define WIDTH_LEFT   4

set width to lw

WIDTH_LSHIFT

#define WIDTH_LSHIFT   6

set width to lw + 2^rw-1

WIDTH_MAX

#define WIDTH_MAX   0

set width to the max of lw, rw

WIDTH_MAX1

#define WIDTH_MAX1   1

set width to max of lw, rw + 1

WIDTH_RIGHT

#define WIDTH_RIGHT   5

set width to rw

WIDTH_SUM

#define WIDTH_SUM   2

set width to sum of lw, rw

WIDTH_UPDATE

#define WIDTH_UPDATE

(

mode

)

Value:

  if (width) {                                  \
    if (mode == WIDTH_MAX) {                    \
      *width = MAX(lw,rw);                      \
    }                                           \
    else if (mode == WIDTH_MAX1) {              \
      *width = MAX(lw,rw)+1;                    \
    }                                           \
    else if (mode == WIDTH_SUM) {               \
      *width = lw+rw;                           \
    }                                           \
    else if (mode == WIDTH_BOOL) {              \
      *width = 1;                               \
    }                                           \
    else if (mode == WIDTH_LEFT) {              \
      *width = lw;                              \
    }                                           \
    else if (mode == WIDTH_RIGHT) {             \
      *width = rw;                              \
    }                                           \
    else if (mode == WIDTH_LSHIFT) {            \
      *width = lw + ((1 << rw)-1);              \
    }                                           \
  }