hwcalc

hwcalc, or hc, is an arbitrary bit width calculator.

Documentation

Refer to the man page at docs/man/hc.1, use e.g.

$ man -l docs/man/hc.1

There is also a rendered version available at https://hllmn.net/man/hc.1.

Build

The Cargo package manager can be used to fetch dependencies and build hc:

$ cargo build --release

The resulting binary will be located at target/release/hc.

Install

The makefile has a rule for installing the hc binary and the man page:

# make install

There is also an uninstall rule:

# make uninstall

Alternatively, hc can be installed from crates.io via Cargo:

cargo install hwcalc

This will install the hc binary in bin/hc under the Cargo root folder (typically ~/.cargo) but will not install the man page.

Examples

hc mostly works like a typical calculator, one can enter expressions that will be evaluated:

> (2 + 7) * 0xd
117
 = 0b111_0101
 = 0o165
 = 0x75

Numbers can be given a specific width with a type specifier:

> 77u8
77
 = 0b0100_1101
 = 0o115
 = 0x4d

For negative numbers, the non-decimal representations will display the two's complement value:

> -77i8
-77 (= 179)
 = 0b1011_0011
 = 0o263
 = 0xb3

The signedness of a number affects how it is extended when operands differ in width:

> 32u8 + (-1)'i4
31
 = 0b0001_1111
 = 0o037
 = 0x1f
> 32u8 + (-1)'u4
47
 = 0b0010_1111
 = 0o057
 = 0x2fa

Values may not only have integer values, they may also contain a fractional part:

> 10/4
2.5 (= 5/2)
 = 0b10.1
 = 0o2.4
 = 0x2.8

By default, the precision is infinite, if a value cannot be represented by a finite number of digits, infinitively repeating sequences of digits will be enclosed with parentheses:

> 1/3
0.(3) (= 1/3)
 = 0b0.(01)
 = 0o0.(25)
 = 0x0.(5)

If a fractional width is specified, the fractional part will be truncated:

> 1/3q.8
0.332_031_25 (= 85/256)
 = 0b0.0101_0101
 = 0o0.252
 = 0x0.55

Negative numbers with an unspecified integer width will have an infinitively repeating digit in the integer part for non-decimal bases:

> -5.25
-5.25 (= -21/4)
 = 0b(1)010.11
 = 0o(7)2.6
 = 0x(f)a.c