| """ | |
| 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], | |
| ) |