When did Intel undergo the SEX change?

Question

I am reading the book "The 8086 / 8088 Primer Second Edition" by Stephen P Morse. In it on page 54, it says

The 8086 provides instructions to facilitate the task of sign extension. These instructions were initially named SEX (sign extend) but were later renamed to [...] CBW (convert byte to word), and CWD (convert word to double word).

What Intel chip provided the primitive SEX (as documented) and what was the last chip produced before Intel underwent the SEX change documenting the new SEX-equivalent differently.

Answer 1

What Intel chip provided the primitive SEX and what was the last chip produced before Intel underwent the SEX change?

None, as that's a function which is only needed if a CPU operates on words longer than 8 bit - something no previous 8 bit (intel) CPU did.

It was a new instruction created for the 8086, so a 8 bit value could be sign extended to 16 bit for further 16 bit operations. Mr. Morse, who did the whole instruction level design for the 8086, named it SEX in his design, but got overruled later on.

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So if you excuse extending the pun, it was never a girl, the proud father just hoped for one :)

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As a side note, as Martin Rosenau reminded me in his comment, the Motorola 6809, released the same year as the 8086, did call their sign extension operation SEX, which extended an 8 bit value in accumulator B into the 16 bit accumulator D (where B is the lower half anyway).

Answer 2

The first CMOS microprocessor, the CDP1802, has a 4-bit "X" register which is used to select one of 16 registers for use with many opcodes including those for arithmetic and bitwise operations. That particular chip uses 16 opcodes 0xE0 through 0xEF, called "SEX 0" through "SEX 15", to set X to one of 16 values. I'm unaware of any Intel chips making use of that mnemonic, however.