Merge pull request #3654 from jangko/vm_uinttouint64conv

fixed #2514 unable to echo uint8-32 at compile time

1 files changed, 8 insertions, 1 deletions

diff --git a/compiler/vm.nim b/compiler/vm.nim
index 0e63daf89..895653652 100644
--- a/compiler/vm.nim
+++ b/compiler/vm.nim
@@ -359,7 +359,14 @@ proc opConv*(dest: var TFullReg, src: TFullReg, desttyp, srctyp: PType): bool =
       of tyFloat..tyFloat64:
         dest.intVal = int(src.floatVal)
       else:
-        dest.intVal = src.intVal and ((1 shl (desttyp.size*8))-1)
+        let srcDist = (sizeof(src.intVal) - srctyp.size) * 8
+        let destDist = (sizeof(dest.intVal) - desttyp.size) * 8
+        when system.cpuEndian == bigEndian:
+          dest.intVal = (src.intVal shr srcDist) shl srcDist
+          dest.intVal = (dest.intVal shr destDist) shl destDist
+        else:
+          dest.intVal = (src.intVal shl srcDist) shr srcDist
+          dest.intVal = (dest.intVal shl destDist) shr destDist
     of tyFloat..tyFloat64:
       if dest.kind != rkFloat:
         myreset(dest); dest.kind = rkFloat