SPRUIY2A November   2024  – March 2025 F29H850TU , F29H859TU-Q1

 

  1.   1
  2.   Read This First
    1.     About This Manual
    2.     Related Documentation from Texas Instruments
    3.     Glossary
    4.     Support Resources
    5.     Trademarks
  3. 1Architecture Overview
    1. 1.1 Introduction to the CPU
    2. 1.2 Data Type
    3. 1.3 C29x CPU System Architecture
      1. 1.3.1 Emulation Logic
      2. 1.3.2 CPU Interface Buses
    4. 1.4 Memory Map
  4. 2Central Processing Unit (CPU)
    1. 2.1 C29x CPU Architecture
      1. 2.1.1 Features
      2. 2.1.2 Block Diagram
    2. 2.2 CPU Registers
      1. 2.2.1 Addressing Registers (Ax/XAx)
      2. 2.2.2 Fixed-Point Registers (Dx/XDx)
      3. 2.2.3 Floating-Point Register (Mx/XMx)
      4. 2.2.4 Program Counter (PC)
      5. 2.2.5 Return Program Counter (RPC)
      6. 2.2.6 Status Registers
        1. 2.2.6.1 Interrupt Status Register (ISTS)
        2. 2.2.6.2 Decode Phase Status Register (DSTS)
        3. 2.2.6.3 Execute Phase Status Register (ESTS)
    3. 2.3 Instruction Packing
      1. 2.3.1 Standalone Instructions and Restrictions
      2. 2.3.2 Instruction Timeout
    4. 2.4 Stacks
      1. 2.4.1 Software Stack
      2. 2.4.2 Protected Call Stack
      3. 2.4.3 Real Time Interrupt / NMI Stack
  5. 3Interrupts
    1. 3.1 CPU Interrupts Architecture Block Diagram
    2. 3.2 RESET, NMI, RTINT, and INT
      1. 3.2.1 RESET (CPU reset)
        1. 3.2.1.1 Required Instructions (RESET)
      2. 3.2.2 NMI (Non-Maskable Interrupt)
        1. 3.2.2.1 Blocking and Masking (NMI)
        2. 3.2.2.2 Signal Propagation (NMI)
        3. 3.2.2.3 Stack (NMI)
        4. 3.2.2.4 Required Instructions (NMI)
      3. 3.2.3 RTINT (Real-Time Interrupt)
        1. 3.2.3.1 Blocking and Masking (RTINT)
        2. 3.2.3.2 Signal Propagation (RTINT)
        3. 3.2.3.3 Stack (RTINT)
        4. 3.2.3.4 Required Instructions (RTINT)
      4. 3.2.4 INT (Low-Priority Interrupt)
        1. 3.2.4.1 Blocking and Masking (INT)
        2. 3.2.4.2 Signal Propagation (INT)
        3. 3.2.4.3 Stack (INT)
    3. 3.3 Conditions Blocking Interrupts
      1. 3.3.1 ATOMIC Counter
    4. 3.4 CPU Interrupt Control Registers
      1. 3.4.1 Interrupt Status Register (ISTS)
      2. 3.4.2 Decode Phase Status Register (DSTS)
      3. 3.4.3 Interrupt-Related Stack Registers
    5. 3.5 Interrupt Nesting
      1. 3.5.1 Interrupt Nesting Example Diagram
    6. 3.6 Security
      1. 3.6.1 Overview
      2. 3.6.2 LINK
      3. 3.6.3 STACK
      4. 3.6.4 ZONE
  6. 4Addressing Modes
    1. 4.1 Addressing Modes Overview
      1. 4.1.1 Documentation and Implementation
      2. 4.1.2 List of Addressing Mode Types
        1. 4.1.2.1 Additional Types of Addressing
      3. 4.1.3 Addressing Modes Summarized
    2. 4.2 Addressing Mode Fields
      1. 4.2.1 ADDR1 Field
      2. 4.2.2 ADDR2 Field
      3. 4.2.3 ADDR3 Field
      4. 4.2.4 DIRM Field
      5. 4.2.5 Additional Fields
    3. 4.3 Alignment and Pipeline Considerations
      1. 4.3.1 Alignment
      2. 4.3.2 Pipeline Considerations
    4. 4.4 Types of Addressing Modes
      1. 4.4.1 Direct Addressing
      2. 4.4.2 Pointer Addressing
        1. 4.4.2.1 Pointer Addressing with #Immediate Offset
        2. 4.4.2.2 Pointer Addressing with Pointer Offset
        3. 4.4.2.3 Pointer Addressing with #Immediate Increment/Decrement
        4. 4.4.2.4 Pointer Addressing with Pointer Increment/Decrement
      3. 4.4.3 Stack Addressing
        1. 4.4.3.1 Allocating and De-allocating Stack Space
      4. 4.4.4 Circular Addressing Instruction
      5. 4.4.5 Bit Reversed Addressing Instruction
  7. 5Safety and Security Unit (SSU)
    1. 5.1 SSU Overview
    2. 5.2 Links and Task Isolation
    3. 5.3 Sharing Data Outside Task Isolation Boundary
    4. 5.4 Protected Call and Return
  8. 6Emulation
    1. 6.1 Overview of Emulation Features
    2. 6.2 Debug Terminology
    3. 6.3 Debug Interface
    4. 6.4 Execution Control Mode
    5. 6.5 Breakpoints, Watchpoints, and Counters
      1. 6.5.1 Software Breakpoint
      2. 6.5.2 Hardware Debugging Resources
        1. 6.5.2.1 Hardware Breakpoint
        2. 6.5.2.2 Hardware Watchpoint
        3. 6.5.2.3 Benchmark Counters
      3. 6.5.3 PC Trace
  9. 7Revision History

4.4.2.2 Pointer Addressing with Pointer Offset

The Pointer Addressing with Pointer Offset type allows indirect read or write access to any location in the 32-bit memory space with the pointer address (base address register) from one of the addressing registers, A0 to A14, and an offset provided by an additional pointer (index register) in the instruction.

This structure allows for easy data array access using a variable index. An example of this can be demonstrated with a 32-bit integer array. If the eighth int in the array is needed, the element can be accessed as follows:

; Because the array is of type int, each element is 4 bytes (32 bits) long.
;    So the index must be multiplied by 4 (which is the same as <<2)
; Starting parameters:
;    int arr[7] = 12
;    A2 = arr (base address)
;    A0 = i (index) = 7 (the eigth int in the array)

LD.32 D0,*(A2+A0<<2)    ; D0 = arr + (7<<2 byte offset)

; Result:
;    D0 = 12
  • 8-bit accesses do not need the index "i" to be multiplied (no shift needed). 16-bit accesses require "i" to be multiplied by 2 (<<1) for 2-byte alignment.
  • 32-bit accesses require "i" to be multiplied by 4 (<<2) for 4-byte alignment.
  • 64-bit accesses require "i" to be multiplied by 8 (<<3) for 8-byte alignment.

The offset provided from the register and shift is added to the base register using a full 32-bit unsigned ADD operation. If the value overflows, the value wraps around.

This allows for negative index values to wrap around:

; Starting parameters:
;    A2 = arr =  8 = 0x0000 0008 (base address at 8th byte in memory space)
;    A0 = i   = -1 = 0xFFFF FFFF (index at -1)
*(A2+A0) = 8 + (-1) = 7th byte in memory space
Note: All data accesses must be aligned to the nearest word size. See Section 4.3.1 for more details and cautions regarding alignment.