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2 changes: 1 addition & 1 deletion content/english/hpc/architecture/assembly.md
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Expand Up @@ -55,7 +55,7 @@ Most instructions write their result into the first operand, which can also be i

**Registers** are named `rax`, `rbx`, `rcx`, `rdx`, `rdi`, `rsi`, `rbp`, `rsp`, and `r8`-`r15` for a total of 16 of them. The "letter" ones are named like that for historical reasons: `rax` is "accumulator," `rcx` is "counter," `rdx` is "data" and so on — but, of course, they don't have to be used only for that.

There are also 32-, 16-bit and 8-bit registers that have similar names (`rax` → `eax` → `ax` → `al`). They are not fully separate but *aliased*: the lowest 32 bits of `rax` are `eax`, the lowest 16 bits of `eax` are `ax`, and so on. This is made to save die space while maintaining compatibility, and it is also the reason why basic type casts in compiled programming languages are usually free.
There are also 32-bit, 16-bit and 8-bit registers that have similar names (`rax` → `eax` → `ax` → `al`). They are not fully separate but *aliased*: the lowest 32 bits of `rax` are `eax`, the lowest 16 bits of `eax` are `ax`, and so on. This is made to save die space while maintaining compatibility, and it is also the reason why basic type casts in compiled programming languages are usually free.

These are just the *general-purpose* registers that you can, with [some exceptions](../functions), use however you like in most instructions. There is also a separate set of registers for [floating-point arithmetic](/hpc/arithmetic/float), a bunch of very wide registers used in [vector extensions](/hpc/simd), and a few special ones that are needed for [control flow](../loops), but we'll get there in time.

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