The following macro functions enable you to read and write bits to and from the control register. For details, see Set Operations. For ItaniumŪ-based systems, these macros do not allow you to access all of the bits of the FPSR. See the descriptions for the getfpsr() and setfpsr() intrinsics in the Native Intrinsics for Itanium Instructions topic.
| Exception State Macros | Macro Arguments |
|---|---|
| _MM_SET_EXCEPTION_STATE(x) | _MM_EXCEPT_INVALID |
| _MM_GET_EXCEPTION_STATE() | _MM_EXCEPT_DIV_ZERO |
| _MM_EXCEPT_DENORM | |
| Macro Definitions Write to and read from the sixth-least significant control register bit, respectively. |
_MM_EXCEPT_OVERFLOW |
| _MM_EXCEPT_UNDERFLOW | |
| _MM_EXCEPT_INEXACT |
The following example tests for a divide-by-zero exception.
| Exception Mask Macros | Macro Arguments |
|---|---|
| _MM_SET_EXCEPTION_MASK(x) | _MM_MASK_INVALID |
| _MM_GET_EXCEPTION_MASK () | _MM_MASK_DIV_ZERO |
| _MM_MASK_DENORM | |
| Macro Definitions Write to and read from the seventh through twelfth control register bits, respectively. Note: All six exception mask bits are always affected. Bits not set explicitly are cleared. |
_MM_MASK_OVERFLOW |
| _MM_MASK_UNDERFLOW | |
| _MM_MASK_INEXACT |
The following example masks the overflow and underflow exceptions and unmasks all other exceptions.
| Exception Mask with _MM_MASK_OVERFLOW and _MM_MASK_UNDERFLOW |
|---|
| _MM_SET_EXCEPTION_MASK(MM_MASK_OVERFLOW | _MM_MASK_UNDERFLOW) |
| Rounding Mode | Macro Arguments |
|---|---|
| _MM_SET_ROUNDING_MODE(x) | _MM_ROUND_NEAREST |
| _MM_GET_ROUNDING_MODE() | _MM_ROUND_DOWN |
| Macro Definition Write to and read from bits thirteen and fourteen of the control register. |
_MM_ROUND_UP |
| _MM_ROUND_TOWARD_ZERO |
The following example tests the rounding mode for round toward zero.
| Rounding Mode with _MM_ROUND_TOWARD_ZERO |
|---|
| if (_MM_GET_ROUNDING_MODE() == _MM_ROUND_TOWARD_ZERO)
{ /* Rounding mode is round toward zero */ } |
| Flush-to-Zero Mode | Macro Arguments |
|---|---|
| _MM_SET_FLUSH_ZERO_MODE(x) | _MM_FLUSH_ZERO_ON |
| _MM_GET_FLUSH_ZERO_MODE() | _MM_FLUSH_ZERO_OFF |
| Macro Definition Write to and read from bit fifteen of the control register. |
The following example disables flush-to-zero mode.
| Flush-to-Zero Mode with _MM_FLUSH_ZERO_OFF |
|---|
| _MM_SET_FLUSH_ZERO_MODE(_MM_FLUSH_ZERO_OFF) |