The 'Assume' page allows specification of values of register which remain constant in course of program execution.
This feature is necessary for compilers that access global variables with a relative addressing mode to a certain CPU register (typically the A5 on 68k CPUs). To access a certain variable the register value must be known to establish the address of the variable. If the CPU is running, it must be stopped to read out the register unless the value of the register is specified in this dialog.
If the value of a certain register is required but can not be accessed (CPU running, halted etc.), its assumed value is used.
Debug Options, Assume page
Assume non self modifying code (cache read accesses to program regions) - If this option is checked, read accesses to program regions are cached.