68040 Registers

68000 Registers

1. General Purpose Registers

   • D0 - D7 (Data Registers)

   • A0 - A7 (Address Registers)

2. Stack Pointer

   • A7 (User Stack Pointer, USP)

   • SSP (Supervisor Stack Pointer)

3. Program Counter

   • PC (Program Counter)

4. Status Register

   • SR (Status Register)

5. Condition Code Register

   • CCR (Condition Code Register)

68040 Registers

The 68040 includes all the registers of the 68000 with the following enhancements:

1. Cache Control Registers

   • CACR (Cache Control Register)

   • Used to control the on-chip cache.

2. Address Space Registers

   • ASID (Address Space Identifier)

   • Used for virtual memory management.

3. Additional Control Registers

   • TC (Translation Control Register)

   • TT0, TT1 (Transparent Translation Registers)

   • Used for memory management and translation.

4. Vector Base Register (VBR)

   • Allows relocation of the exception vector table, providing more flexibility in handling exceptions.

5. Alternate Function Code Registers (SFC and DFC)

   • SFC (Source Function Code Register)

   • DFC (Destination Function Code Register)

   • These registers are used to control the function codes for memory access, allowing more sophisticated memory management.

6. Floating Point Unit (FPU) Registers

   • FP0 - FP7 (Floating Point Data Registers)

   • Used for floating-point arithmetic operations.

Summary

• The 68040 includes all the registers of the 68000.

• The 68040 adds Cache Control Registers (CACR) for cache management.

• The 68040 introduces Address Space Identifier (ASID) for virtual memory management.

• The 68040 includes additional control registers like Translation Control Register (TC) and Transparent Translation Registers (TT0, TT1) for advanced memory management.

• The 68040 retains the Vector Base Register (VBR) and Source Function Code Register (SFC) and Destination Function Code Register (DFC) from the 68010 for enhanced memory management and exception handling.

• The 68040 introduces Floating Point Unit (FPU) Registers (FP0 - FP7) for floating-point arithmetic operations.

These enhancements in the 68040 provide improved performance, advanced memory management, and additional features compared to the 68000.