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added more explication of register meanings - thank you to Marc G.

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section_1/regs/README.md
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# Section 1 / Interlude - Registers
We have discussed and used registers in the previous chapters without explanation. This chapter
introduces the concept of registers and explains why registers are critical.
We have discussed and used registers in the previous chapters without
explanation. This chapter introduces the concept of registers and
explains why registers are critical.
## Types of Registers
Of general interest, the ARM 64 bit ISA offers a large register set for integer types and another
for floating point types.
Of general interest, the ARM 64 bit ISA offers a large register set for
integer types and another for floating point types.
The register set designed for integer types are indicated by `x` and `w` variants. The two
variations are coincident - `w0` for example, is the same underlying register as `x0`. The
choice of letter (`x` or `w`) determines how the register is interpreted.
The register set designed for integer types are indicated by `x` and `w`
variants. The two variations are coincident - `w0` for example, is the
same underlying register as `x0`. The choice of letter (`x` or `w`)
determines how the register is interpreted.
* The `x` registers are for `long` integers and addresses.
* The `w` registers are used for the narrower integer types.
* The `w` registers are used for the narrower integer types. While `w`
stands for *word*, these registers are also used for `short` and
`char`.
The registers used for floating point types (and vector operations) are coincident:
* `q` registers are a massive 16 bytes wide.
* `v` registers are also 16 bytes wide and are synonyms for the `q` registers.
* `d` registers for `doubles` which are 8 bytes wide. 2 per `v`.
* `s` registers for `floats` which are 4 bytes wide. 4 per `v`.
* `h` registers for `half precisions floats` which are 2 bytes wide. 8 per `v`.
* `q` registers are a massive 16 bytes wide - quad words.
* `v` registers are also 16 bytes wide and are synonyms for the `q`
registers.
* `d` registers for `doubles` which are 8 bytes wide - double precision.
2 per `v`.
* `s` registers for `floats` which are 4 bytes wide - single precision.
4 per `v`.
* `h` registers for `half precisions floats` which are 2 bytes wide. 8
per `v`.
* `b` registers for byte operations. 16 per `v`.
## Why Registers