avr:avr-gcc-regs
Table of Contents
AVR GCC calling conventions
Thanks Paulo Soares psoares@consiste.pt
Register Usage
| Parameters | Param 1 | Param 2 | Param 3 | Param 4 |
|---|---|---|---|---|
| f(p8,p8) | R25 | R24 | ~~ | ~~ |
| f(p8,p8,p8,p8) | R25 | R24 | R23 | R22 |
| f(p16,p16) | R25:24# | R23:22 | ~~ | ~~ |
| f(p16,p16,p16) | R25:24 | R23:22 | R21:20 | ~~ |
| f(p32,p32) | R25:24:23:22# | R21:20:19:18 | ~~ | ~~ |
| f(p32,p32,p32) | R25:24:23:22 | R21:20:19:18 | R17:16:15:14 | ~~ |
| f(p8,p16,p32) | R25 | R24:23 | R22:21:20:19 | ~~ |
# MSB left, LSB right
Return Value
| Size | Registers |
|---|---|
| p8 | R25:24## |
| p16 | R25:24 |
| p32 | R25:24:23:22 |
## R25 is cleared
avr/avr-gcc-regs.txt ยท Last modified: 2005/10/21 17:55 by 127.0.0.1