Fix sign of bitfields only if type is signed. Fixes #1.

Jethro Beekman · Jethro Beekman · commit ac673405d576 · 2014-10-03T10:14:51.000-07:00
diff --git a/magic3.hpp b/magic3.hpp
@@ -165,7 +165,7 @@
 					bitfield_mask_t bitfield_mask=bit_mask(bitfieldTable[parameter]>>16);
 					uint16_t bitfield_offset=bitfieldTable[parameter]&0xffff;
 					T unsignedT=((*(bitfield_mask_t*)this)>>bitfield_offset)&bitfield_mask;
-					if (((bitfield_mask+1)>>1)&unsignedT) //negative
+					if (std::is_signed<T>::value && ((bitfield_mask+1)>>1)&unsignedT) //negative
 					{
 						unsignedT|=~bitfield_mask; //sign-extend
 					}

Original file line number	Diff line number	Diff line change
`@@ -165,7 +165,7 @@`
`165`	`165`	`bitfield_mask_t bitfield_mask=bit_mask(bitfieldTable[parameter]>>16);`
`166`	`166`	`uint16_t bitfield_offset=bitfieldTable[parameter]&0xffff;`
`167`	`167`	`T unsignedT=(((bitfield_mask_t)this)>>bitfield_offset)&bitfield_mask;`
`168`		`- if (((bitfield_mask+1)>>1)&unsignedT) //negative`
	`168`	`+ if (std::is_signed<T>::value && ((bitfield_mask+1)>>1)&unsignedT) //negative`
`169`	`169`	`{`
`170`	`170`	`unsignedT\|=~bitfield_mask; //sign-extend`
`171`	`171`	`}`