Files
iverilog/tgt-vvp
Cary R 6bbf97a05d Warn that a signed part select may not work for signals < 32 bits.
If a signed signal is driving a part select in a CA and the width
is less than 32 bits. the value will be zero extended and will
not work for negative values. This patch adds a warning that this
could happen. This will be fixed in development.
(cherry picked from commit e1af002a32)
2009-09-24 13:44:22 -07:00
..
2008-09-29 18:06:47 -07:00
2008-09-29 18:06:47 -07:00
2008-09-29 18:06:47 -07:00

THE VVP TARGET

SYMBOL NAME CONVENTIONS

There are some naming conventions that the vp target uses for
generating symbol names.

* wires and regs

Nets and variables are named V_<full-name> where <full-name> is the
full hierarchical name of the signal.

* Logic devices

Logic devices (and, or, buf, bufz, etc.) are named L_<full_name>. In
this case the symbol is attached to a functor that is the output of
the logic device.


GENERAL FUNCTOR WEB STRUCTURE

The net of gates, signals and resolvers is formed from the input
design. The basic structure is wrapped around the nexus, which is
represented by the ivl_nexus_t.

Each nexus represents a resolved value. The input of the nexus is fed
by a single driver. If the nexus in the design has multiple drivers,
the drivers are first fed into a resolver (or a tree of resolvers) to
form a single output that is the nexus.

The nexus, then, feeds its output to the inputs of other gates, or to
the .net objects in the design.