Prevent Register Retiming
The Prevent
register retiming option controls whether or not to globally disable
retiming. When set to disabled, the Compiler automatically performs
register retiming optimizations, moving registers through combinational logic. When set to
enabled, the Compiler prevents any retiming optimizations from
happening on a global scale.
Optionally, assign Allow Register Retiming to any design entity or instance to override
Prevent register retiming for specific portions of
the design. Click to specify entity- and instance-level assignments, or use the following syntax
to make the assignment in the .qsf directly.
Disable register retiming for entity abc
set_global_assignment –name ALLOW_REGISTER_RETIMING ON set_instance_assignment –name ALLOW_REGISTER_RETIMING OFF –to “abc|” set_instance_assignment –name ALLOW_REGISTER_RETIMING ON –to “abc|def|”
Disable register retiming for the whole design, except for registers in entity abc
set_global_assignment –name ALLOW_REGISTER_RETIMING OFF set_instance_assignment –name ALLOW_REGISTER_RETIMING ON –to “abc|” set_instance_assignment –name ALLOW_REGISTER_RETIMING OFF –to “abc|def|”