Fix case of differing signs

mborland · mborland · commit 556518dbe2c0 · 2025-11-21T11:15:06.000+01:00
diff --git a/include/boost/decimal/detail/add_impl.hpp b/include/boost/decimal/detail/add_impl.hpp
@@ -122,7 +122,7 @@ constexpr auto add_impl(const T& lhs, const T& rhs) noexcept -> ReturnType
                 {
                     if (big_rhs != 0U)
                     {
-                        if (lhs.isneg())
+                        if (lhs.isneg() != rhs.isneg())
                         {
                             if (is_power_of_10(big_lhs))
                             {
@@ -148,7 +148,7 @@ constexpr auto add_impl(const T& lhs, const T& rhs) noexcept -> ReturnType
                 {
                     if (big_lhs != 0U)
                     {
-                        if (rhs.isneg())
+                        if (rhs.isneg() != lhs.isneg())
                         {
                             --big_rhs;
                             big_rhs *= 10U;
@@ -282,7 +282,7 @@ constexpr auto d128_add_impl(T lhs_sig, U lhs_exp, bool lhs_sign,
             {
                 if (rhs_sig != 0U)
                 {
-                    if (lhs_sign)
+                    if (lhs_sign != rhs_sign)
                     {
                         if (is_power_of_10(lhs_sig))
                         {
@@ -308,7 +308,7 @@ constexpr auto d128_add_impl(T lhs_sig, U lhs_exp, bool lhs_sign,
             {
                 if (lhs_sig != 0U)
                 {
-                    if (rhs_sign)
+                    if (rhs_sign != lhs_sign)
                     {
                         --rhs_sig;
                         rhs_sig *= 10U;

Original file line number	Diff line number	Diff line change
`@@ -122,7 +122,7 @@ constexpr auto add_impl(const T& lhs, const T& rhs) noexcept -> ReturnType`
`122`	`122`	`{`
`123`	`123`	`if (big_rhs != 0U)`
`124`	`124`	`{`
`125`		`- if (lhs.isneg())`
	`125`	`+ if (lhs.isneg() != rhs.isneg())`
`126`	`126`	`{`
`127`	`127`	`if (is_power_of_10(big_lhs))`
`128`	`128`	`{`
`@@ -148,7 +148,7 @@ constexpr auto add_impl(const T& lhs, const T& rhs) noexcept -> ReturnType`
`148`	`148`	`{`
`149`	`149`	`if (big_lhs != 0U)`
`150`	`150`	`{`
`151`		`- if (rhs.isneg())`
	`151`	`+ if (rhs.isneg() != lhs.isneg())`
`152`	`152`	`{`
`153`	`153`	`--big_rhs;`
`154`	`154`	`big_rhs *= 10U;`
`@@ -282,7 +282,7 @@ constexpr auto d128_add_impl(T lhs_sig, U lhs_exp, bool lhs_sign,`
`282`	`282`	`{`
`283`	`283`	`if (rhs_sig != 0U)`
`284`	`284`	`{`
`285`		`- if (lhs_sign)`
	`285`	`+ if (lhs_sign != rhs_sign)`
`286`	`286`	`{`
`287`	`287`	`if (is_power_of_10(lhs_sig))`
`288`	`288`	`{`
`@@ -308,7 +308,7 @@ constexpr auto d128_add_impl(T lhs_sig, U lhs_exp, bool lhs_sign,`
`308`	`308`	`{`
`309`	`309`	`if (lhs_sig != 0U)`
`310`	`310`	`{`
`311`		`- if (rhs_sign)`
	`311`	`+ if (rhs_sign != lhs_sign)`
`312`	`312`	`{`
`313`	`313`	`--rhs_sig;`
`314`	`314`	`rhs_sig *= 10U;`