| """ |
| Supported PCF commands: |
| * set_io <net> <pad> - constrain a given <net> to a given physical <pad> in eFPGA pinout. |
| * set_clk <pin> <net> - constrain a given global clock <pin> to a given <net> |
| Every tile where <net> is present will be constrained to use a given global clock. |
| """ |
| |
| from collections import namedtuple |
| import re |
| |
| PcfIoConstraint = namedtuple('PcfIoConstraint', 'net pad line_str line_num') |
| PcfClkConstraint = namedtuple('PcfClkConstraint', 'pin net') |
| |
| |
| def parse_simple_pcf(f): |
| """ Parse a simple PCF file object and yield PcfIoConstraint objects. """ |
| for line_number, line in enumerate(f): |
| line_number += 1 |
| |
| # Remove comments. |
| args = re.sub(r"#.*", "", line.strip()).split() |
| |
| if not args: |
| continue |
| |
| # Ignore arguments. |
| args = [arg for arg in args if arg[0] != '-'] |
| assert len(args) == 3, args |
| |
| if args[0] == 'set_io': |
| |
| yield PcfIoConstraint( |
| net=args[1], |
| pad=args[2], |
| line_str=line.strip(), |
| line_num=line_number, |
| ) |
| |
| if args[0] == 'set_clk': |
| |
| yield PcfClkConstraint( |
| pin=args[1], |
| net=args[2], |
| ) |
