simplify mp_complement

minad · minad · commit 3b710fbd7e4d · 2019-11-04T15:41:33.000+01:00
diff --git a/mp_complement.c b/mp_complement.c
@@ -6,7 +6,8 @@
 /* b = ~a */
 mp_err mp_complement(const mp_int *a, mp_int *b)
 {
-   mp_err err = mp_neg(a, b);
-   return (err == MP_OKAY) ? mp_sub_d(b, 1uL, b) : err;
+   mp_int a_ = *a;
+   a_.sign = ((a_.sign == MP_ZPOS) && !mp_iszero(a)) ? MP_NEG : MP_ZPOS;
+   return mp_sub_d(&a_, 1uL, b);
 }
 #endif

Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,8 @@`
`6`	`6`	`/* b = ~a */`
`7`	`7`	`mp_err mp_complement(const mp_int a, mp_int b)`
`8`	`8`	`{`
`9`		`- mp_err err = mp_neg(a, b);`
`10`		`- return (err == MP_OKAY) ? mp_sub_d(b, 1uL, b) : err;`
	`9`	`+ mp_int a_ = *a;`
	`10`	`+ a_.sign = ((a_.sign == MP_ZPOS) && !mp_iszero(a)) ? MP_NEG : MP_ZPOS;`
	`11`	`+ return mp_sub_d(&a_, 1uL, b);`
`11`	`12`	`}`
`12`	`13`	`#endif`