Important: The information in this document is obsolete and should not be used for new development.
Chapter 12 - Assembly-Language Environmental Controls
This chapter describes how to use assembly-language instructions to control the floating-point environment (rounding direction and exception flags) described in Chapter 4, "Environmental Controls." The current state of the floating-point environment is stored in the Floating-Point Status and Control Register and summarized in the Condition Register. This chapter describes exactly how these two registers store the environment. Then it describes the PowerPC assembler instructions you can use to test or change the environment.Read this chapter to learn how to access and manipulate the floating-point environment in assembly language or to learn how the PowerPC architecture stores the floating-point environment.
Chapter Contents
- The Floating-Point Environment
- The Floating-Point Status and Control Register
- The Condition Register
- Inquiries: Class and Sign
- Floating-Point Result Flags and Condition Codes
- Example: Determining Class
- Setting the Rounding Direction
- Floating-Point Exceptions
- Exception Bits in the FPSCR
- Signaling and Clearing Floating-Point Exceptions
- Enabling and Disabling Floating-Point Exceptions
- Testing for Floating-Point Exceptions
- Saving and Restoring the Floating-Point Environment