| ||||
| Home Products Download Events Support | ||||
Technical Support
On-Line Manuals
C166 User's Guide
C166 Introduction Compiling Programs Language Extensions Preprocessor 
Advanced Programming Sections, Classes, and Groups 
Special Sections Locating Sections Customization Files Startup Code STARTUP.A66 START167.A66 START_V2.A66 START_V3.A66 Basic I/O Memory Allocation TRAPS.C Optimizer Optimizer Options General Optimizations 80C166-Specific Optimizations Global Register Coloring DPP Registers Stacks System Stack User Stack Stack Sizes System Stack Size User Stack Size XBUS Memory and Peripherals On-chip XRAM XBUS Peripherals Interfacing C to Assembler Function Parameters Function Return Values Using the SRC Directive Register Usage Example Routines TINY Model SMALL Model COMPACT Model MEDIUM Model LARGE Model Data Storage Formats Bit Variables 1-byte Scalars 2-byte Scalars 4-byte Scalars float Scalars float Errors double Scalars double Errors near Pointers far Pointers huge Pointers xhuge Pointers Absolute Memory Access Absolute Access Macros Linker Location Controls Debugging Error Messages Library Reference AppendixFunction Return Values
Function return values are always passed using MCU registers. The following table lists the possible return values and the registers used for each.
| Return Type | Register | Description |
|---|---|---|
| bit | R4.0 | Single bit returned in R4.0. |
| char, unsigned char | RL4 | Single byte type returned in RL4. |
| int, unsigned int, near pointer | R4 | Two byte (16-bit) type returned in R4. |
| long, unsigned long, far pointer, huge pointer | R4 & R5 | LSB in R4, MSB in R5. |
| float | R4 & R5 | 32-Bit IEEE format. |
| double | R4-R7 | 64-Bit IEEE format. |
| Contact Site Map Press Privacy | Copyright © 2012 ARM Ltd and ARM Germany GmbH. All rights reserved. |
