when you generate a svf file with the tools from lattice, ispVM, then in the resulting file you can read the following notes in the header about non standard syntax of the file:
! Lattice Semiconductor Corp.
! Lattice Extended Serial Vector Format (.SVF) File.
! This file does not comply with the SVF Standard.
! This file might contain the LOOP and ENDLOOP statements, which do not comply with the SVF standard.
! The Lattice SVF processor will process and repeat the statements in-between the LOOP statement and
! the ENDLOOP statement loop_count number of times.
! 1. support all SVF standard commands inside the loop.
! 2. does not support nested loops.
! LOOP loop_count;
! LOOP 85 ;
! SIR 8 TDI (52);
! RUNTEST IDLE 10 TCK 1.00E+000 SEC;
! SDR 1 TDI (0) // exit loop if passed.
! TDO (1);// loop back if failed.
! ENDLOOP ;
seems not that complicated to enhance the svf reader to support this aadditional loop command.
i have not found a way to disable the use of the loop command in ispVM.