Abd lnker crt sbss fix

[amichai-bd]

This pull request includes significant updates to the initialization and tracking mechanisms in the boot and verification files. The most important changes include restructuring the boot sequence, adding zero-initialization for sections, and introducing new tracking for register writes.

Boot Sequence and Initialization:

• app/crt0/crt0_boot_trap.s: Moved the initialization code to a new init_handler and added zero-initialization loops for .sbss and .bss sections. [1] [2]
• app/crt0/crt0_default.s: Added zero-initialization loops for .sbss and .bss sections in the reset_handler. [1] [2]

Memory Layout:

• app/link.common.ld: Updated the linker script to define and zero-initialize .sbss and .bss sections.

Verification and Tracking:

• verif/big_core_cachel1/tb/trk/big_core_cachel1_trk.vh: Added new trackers for register writes, logging PC, register destination, and data. [1] [2] [3]
• verif/rv32i_ref/tb/rv32i_ref_trk.vh: Introduced a new tracker for register writes in the reference model. [1] [2]

Miscellaneous:

• verif/rv32i_ref/tb/rv32i_ref.sv: Modified DFF assignments to ensure x0 is always zero. [1] [2]
• verif/rv32i_ref/tb/rv32i_ref_tb.sv: Updated the package import to rv32i_ref_pkg.

[amichai-bd]

This pull request includes significant changes to the initialization and tracking mechanisms in the system's startup and verification files. The most important changes include restructuring the initialization sequence, adding new tracking logs for register writes, and updating the linker script to handle uninitialized data sections.

Initialization Sequence Updates:

• app/crt0/crt0_boot_trap.s: Moved CSR and stack initialization to a new init_handler and added zero initialization loops for .sbss and .bss sections. [1] [2] [3]
• app/crt0/crt0_default.s: Added zero initialization loops for .sbss and .bss sections after stack initialization. [1] [2]

Tracking Enhancements:

• verif/big_core_cachel1/tb/trk/big_core_cachel1_ref_trk.vh: Added a new tracker for all writes to the register file, logging the PC, register destination, and data written.
• verif/big_core_cachel1/tb/trk/big_core_cachel1_trk.vh: Added a new tracker for all writes to the register file, similar to the previous file.

Linker Script Updates:

• app/link.common.ld: Added sections for uninitialized small data (.sbss) and uninitialized data (.bss) to the linker script.

Miscellaneous Changes:

• verif/rv32i_ref/tb/rv32i_ref.sv: Modified DFF instantiation to ensure regfile[0] is always zero. [1] [2]
• verif/rv32i_ref/tb/rv32i_ref_tb.sv: Changed package import from common_pkg to rv32i_ref_pkg.
• verif/rv32i_ref/tb/rv32i_ref_trk.vh: Added a new tracker for register writes in the reference model. [1] [2]