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This is not fair compare. Motorola and Intel that time outperforms first RISC machines, because have much better silicone level (even when logic level was not b
by simne 3y ago
This is not fair compare. Motorola and Intel that time outperforms first RISC machines, because have much better silicone level (even when logic level was not best).
But game consoles are fair, as they was specialized machines, made with good silicone and with large scale production.
On the same time, I'm not agree to consider 68020 as genuine CISC machine - I think it is more fair to consider it hybrid - RISC-optimized CISC (or, as it named on rumor talks - "mini on one chip").
I think, genuine CISC machines was most S/360 and some mini-machines, like Alto in which was documented feature to develop your own microcode (in S/360 it was marketed feature with high value, because with custom microcode, 360 could run software compiled for older hardware like 1401 or 7xx/7xxx series).
And I agree with you, RISC achieve market adoption, when micro-processor (one-chip CPU) market share become so large, that these games with compatibility with old machines become non interest financially.
So, as resume, I say, RISC machines are not players of CISC market, they are essentially players of micro-market, which in mid 1980s was not much more than games and terminals for mainframes and mini's (micro with, say 128k RAM is considerable to run accounting for small business but impossible to do more).
In 1990s, RAM become so cheap, micro's swallowed mini's market, and appear clouds, so become possible to run large enterprise accounting on micro hardware. And at that moment, created Alpha, and than AMD-K8, which was essentially Alpha with hardware translator of x86 instructions to RISC.
So, after all these adventures, RISC entered market via back door :)
- simne 3y agoTo avoid misunderstanding, as I understand from mainframe talks, many of them was customizable like modern FPGA machines, as they even considered make custom hardware (imagine, you could order fully custom machine with additional registers, custom ALU, etc), that's why I compare custom microcode of CISC to FPGA, and why I think it is lost feature, just not existing in mini's and in micro's.