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CARM User's Guide
Discontinued
Function Return Values
Function return values are always passed using CPU registers. The following table lists the possible return values and the registers used for each.
| Return Type | Bits | Register | Description |
|---|---|---|---|
| signed char | 8 | R0 | Value returned in the low byte of R0. |
| unsigned char | 8 | R0 | Value returned in the low byte of R0. |
| signed short | 16 | R0 | Value returned in the low half-word of R0. |
| unsigned short | 16 | R0 | Value returned in the low half-word of R0. |
| signed int | 32 | R0 | Value returned in R0. |
| unsigned int | 32 | R0 | Value returned in R0. |
| signed long | 32 | R0 | Value returned in R0. |
| unsigned long | 32 | R0 | Value returned in R0. |
| float | 32 | R0 | Value returned in R0. |
| pointer | 32 | R0 | Value returned in R0. |
| signed long long | 64 | R0-R1 | Low word returned in R0. High word returned in R1. |
| unsigned long long | 64 | R0-R1 | Low word returned in R0. High word returned in R1. |
| double | 64 | R0-R1 | Low word returned in R0. High word returned in R1. |
| struct | R0-R3 | Structs with a total size less than 16 bytes are returned in R0-R3. |
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