diff --git a/src/chipset/neat.c b/src/chipset/neat.c
index 0661f89ee..0aa6fe5b6 100644
--- a/src/chipset/neat.c
+++ b/src/chipset/neat.c
@@ -988,7 +988,7 @@ neat_read(uint16_t port, void *priv)
             if ((dev->indx >= 0x60) && (dev->indx <= 0x6e))
                 ret = dev->regs[dev->indx];
             else if (dev->indx == 0x6f)
-                ret = (dev->regs[dev->indx] & 0xfd) | ~(mem_a20_alt & 0x02);
+                ret = (dev->regs[dev->indx] & 0xfd) | ((~mem_a20_alt) & 0x02);
             break;
 
         default: