gsim 1.1.4

High speed digital logic simulation
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

use crate::id_lists::IdInternal;
use crate::SimulatorData;
use std::num::{NonZeroU16, NonZeroU8};

#[derive(Debug, Clone, Copy)]
enum TimescaleUnit {
    Seconds,
    Milliseconds,
    Microseconds,
    Nanoseconds,
    Picoseconds,
}

impl std::fmt::Display for TimescaleUnit {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let s = match self {
            TimescaleUnit::Seconds => "s",
            TimescaleUnit::Milliseconds => "ms",
            TimescaleUnit::Microseconds => "us",
            TimescaleUnit::Nanoseconds => "ns",
            TimescaleUnit::Picoseconds => "ps",
        };

        f.write_str(s)
    }
}

/// The timescale in a VCD file
#[derive(Debug, Clone, Copy)]
pub struct Timescale {
    unit: TimescaleUnit,
    value: NonZeroU16,
}

impl std::default::Default for Timescale {
    fn default() -> Self {
        Self {
            unit: TimescaleUnit::Nanoseconds,
            value: NonZeroU16::MIN,
        }
    }
}

impl std::fmt::Display for Timescale {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}{}", self.value, self.unit)
    }
}

#[allow(missing_docs)]
impl Timescale {
    pub const fn seconds(seconds: NonZeroU16) -> Self {
        Self {
            unit: TimescaleUnit::Seconds,
            value: seconds,
        }
    }

    pub const fn milliseconds(milliseconds: NonZeroU16) -> Self {
        Self {
            unit: TimescaleUnit::Milliseconds,
            value: milliseconds,
        }
    }

    pub const fn microseconds(microseconds: NonZeroU16) -> Self {
        Self {
            unit: TimescaleUnit::Microseconds,
            value: microseconds,
        }
    }

    pub const fn nanoseconds(nanoseconds: NonZeroU16) -> Self {
        Self {
            unit: TimescaleUnit::Nanoseconds,
            value: nanoseconds,
        }
    }

    pub const fn picoseconds(picoseconds: NonZeroU16) -> Self {
        Self {
            unit: TimescaleUnit::Picoseconds,
            value: picoseconds,
        }
    }
}

pub(crate) fn write_vcd_header<VCD: std::io::Write>(
    data: &SimulatorData,
    vcd: &mut VCD,
    timescale: Timescale,
) -> std::io::Result<()> {
    use cow_utils::CowUtils;

    const VERSION: &str = env!("CARGO_PKG_VERSION");
    let now = chrono::Local::now().format("%A, %B %e %Y, %X");
    writeln!(vcd, "$version Gsim {VERSION} $end")?;
    writeln!(vcd, "$date {now} $end")?;
    writeln!(vcd, "$timescale {timescale} $end")?;
    writeln!(vcd, "$scope module SIM $end")?;
    for (&wire_id, wire_name) in &data.wire_names {
        let wire_name = wire_name.cow_replace(char::is_whitespace, "_");
        let wire_width = data.get_wire_width(wire_id).unwrap();
        let ident = wire_id.to_u32();
        writeln!(vcd, "    $var wire {wire_width} W{ident} {wire_name} $end")?;
    }
    writeln!(vcd, "$upscope $end")?;
    writeln!(vcd, "$enddefinitions $end")?;

    Ok(())
}

pub(crate) fn trace_vcd<VCD: std::io::Write>(
    data: &SimulatorData,
    vcd: &mut VCD,
    time: u64,
) -> std::io::Result<()> {
    writeln!(vcd, "#{time}")?;
    for &wire_id in data.wire_names.keys() {
        let wire_width = data.get_wire_width(wire_id).unwrap();
        let wire_state = data.get_wire_state(wire_id).unwrap();
        let ident = wire_id.to_u32();
        if wire_width > NonZeroU8::MIN {
            writeln!(vcd, "b{} W{ident}", wire_state.display_string(wire_width))?;
        } else {
            writeln!(vcd, "{}W{ident}", wire_state.get_bit_state(0))?;
        }
    }

    Ok(())
}