here is the 1995 paper that the #Spectre paper published in 2019 cites - and don't forget the research was funded by the NSA:
An in-depth analysis of the 80x86 processor families identifies architectural properties that may have unexpected, and undesirable, results in secure computer systems. In addition, reported implementation errors in some processor versions render them undesirable for secure systems because of potential security and reliability problems. In this paper, we discuss the imbalance in scrutiny for hardware protection mechanisms relative to software, and why this imbalance is increasingly difficult to justify as hardware complexity increases. We illustrate this difficulty with examples of architectural subtleties and reported implementation errors.
citeseerx.ist.psu.edu/viewdoc/…
Sibert, O., Porras, P. A., & Lindell, R. (1995, May). The intel 80x86 processor architecture: pitfalls for secure systems. In Proceedings 1995 IEEE Symposium on Security and Privacy (pp. 211-222). IEEE.
