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Comment by AnimalMuppet | Hacker News Reader

But with only four segment registers, you couldn't treat it as that - not unless you only had four objects. So treating it as a sliding window was all you actually could do with it.

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With 6-7 general purpose registers you could have; since anyway only three of them were usable for addressing you constantly had to load from memory. just use MOV ES instead of MOV BX to load a pointer and you actually got to increase your GPRs by one or two. Nobody did it except for larger memory areas which were allocated using farmalloc() or the INT 21h allocator.

x86 has 7 general purpose registers.

Using a bare segment register as a pointer was quite common. That’s what the DOS memory allocation call would return.

I remember that at some point compiler ads would brag that the new "Microland" compiler could do "segment pointers" where only the segment was stored. I don't remember when it was, but it was fairly late in the DOS era.

In retrospect, they seem so useful and obvious but apparently not. I guess the type of person who thinks near/far/huge is extremely complicated found segment pointers even more complicated.

That's almost like saying that with 2 registers you can only do additions with 2 operands. True, but missing the picture. The number of segments is not limited by the number of segment registers, or even (gasp!) by the number of segment descriptors.

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