I need to verify my understanding of 64 bit storage in z/OS. I thought I understood the "bar", but my understanding has been called into question by someone that should know so I need to verify what I think I know.
It was my understanding that addresses with bit 31 "on" (xxxxxxxx xxxxxxxx 1xxxxxxx xxxxxxxx) are considered invalid. This was imposed due to the convention of using the high-bit of a (32 bit) register as a flag. So, we can use storage below the 2 GB line or above the 4 GB line, but not between them. Secondly, if using IARV64, you will never receive storage that includes this 'invalid' area. Did I have it wrong? -- Tony Thigpen
