regcommsgen 0.1.0

Code generator for peripherals with registers over embedded comms
Documentation 
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use serde::{Serialize, Deserialize};
use crate::field_spec::{FieldSpec, FieldPos};
use crate::peripheral_spec::PeripheralSpec;
use crate::endian::Endian;

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct RegisterSpec {
    pub name: String,
    pub address: u64,
    // Size in bytes, up to 8 bytes supported
    pub size: u8,
    pub readable: bool,
    pub writable: bool,
    pub reset_val: Option<u64>,
    pub fields: Vec<FieldSpec>,
    pub access_proc: Option<String>,
    // aliasable
}

impl RegisterSpec {

    pub fn reg_mod_name(&self) -> String {
        stringcase::snake_case(&self.name)
    }

    pub fn reg_method_name(&self) -> String {
        stringcase::snake_case(&self.name)
    }

    pub fn reg_struct_name(&self) -> String {
        stringcase::pascal_case(&self.name)
    }

    pub fn regval_struct_name(&self) -> String {
        format!("{}Val", stringcase::pascal_case(&self.name))
    }

    pub fn regval_word_size(&self) -> u8 {
        let len = self.size;
        if len <= 2 {
            len as u8
        } else if len <= 4 {
            4
        } else if len <= 8 {
            8
        } else {
            panic!("Invalid word size")
        }
    }

    pub fn regval_word_name(&self) -> &'static str {
        match self.regval_word_size() {
            1 => "u8",
            2 => "u16",
            4 => "u32",
            8 => "u64",
            _ => panic!("Invalid word size from regval_word_size"),
        }
    }

    // Commsbuf subscript based on word size and endianness
    // If the word size is the same as the actual register size, then
    // we have no subscript
    pub fn commsbuf_subscript(&self, endian: Endian) -> String {
        let word_size = self.regval_word_size();
        let padding_len = word_size - self.size;
        let (low, high) = if padding_len == 0 {
            return "".to_string()
        } else if matches!(endian, Endian::Big) {
            (padding_len, word_size)
        } else {
            (0, self.size)
        };
        format!("[{low}..{high}]")
    }

    pub fn access_proc_enum(&self) -> String {
        let Some(ref _proc) = self.access_proc else {
            return "crate::AccessProc::Standard".to_string()
        };
        todo!()
    }

    pub fn generate_file(&self, pspec: &PeripheralSpec) -> String {
        let mut out = String::new();
        out.push_str(&format!("use regcomms::{{RegCommsError, RegComms}};\n"));
        out.push_str(&format!("use crate::{};\n", pspec.peripheral_struct_name()));
        out.push_str(&format!("pub struct {}<'a, C: RegComms{}>(pub &'a mut {}<C>);\n", self.reg_struct_name(), pspec.regcomms_params(), pspec.peripheral_struct_name()));
        out.push_str(&format!("impl<'a, C: RegComms{}> {}<'a, C> {{\n", pspec.regcomms_params(), self.reg_struct_name()));
        let endian = pspec.endian();
        if self.readable {
            out.push_str(&format!("    pub fn read(&mut self) -> Result<{}, RegCommsError> {{\n", self.regval_struct_name()));
            out.push_str(&format!("        let mut buf = [0u8; {}];\n", self.regval_word_size()));
            out.push_str(&format!("        self.0.comms_read(0x{:x}, &mut buf{}, {})?;\n", self.address, self.commsbuf_subscript(endian), self.access_proc_enum()));
            out.push_str(&format!("        let val = {}::from_{}_bytes(buf);\n", self.regval_word_name(), endian.abbrev()));
            out.push_str(&format!("        Ok({}(val))\n", self.regval_struct_name()));
            out.push_str(&format!("    }}\n"));
            out.push_str(&format!("    pub async fn read_async(&mut self) -> Result<{}, RegCommsError> {{\n", self.regval_struct_name()));
            out.push_str(&format!("        let mut buf = [0u8; {}];\n", self.regval_word_size()));
            out.push_str(&format!("        self.0.comms_read_async(0x{:x}, &mut buf{}, {}).await?;\n", self.address, self.commsbuf_subscript(endian), self.access_proc_enum()));
            out.push_str(&format!("        let val = {}::from_{}_bytes(buf);\n", self.regval_word_name(), endian.abbrev()));
            out.push_str(&format!("        Ok({}(val))\n", self.regval_struct_name()));
            out.push_str(&format!("    }}\n"));

        }
        if self.writable {
            out.push_str(&format!("    pub fn write(&mut self, val: {}) -> Result<(), RegCommsError> {{\n", self.regval_struct_name()));
            out.push_str(&format!("        let buf = val.0.to_be_bytes();\n"));
            out.push_str(&format!("        self.0.comms_write(0x{:x}, &buf{}, {})?;\n", self.address, self.commsbuf_subscript(endian), self.access_proc_enum()));
            out.push_str(&format!("        Ok(())\n"));
            out.push_str(&format!("    }}\n"));
            out.push_str(&format!("    pub async fn write_async(&mut self, val: {}) -> Result<(), RegCommsError> {{\n", self.regval_struct_name()));
            out.push_str(&format!("        let buf = val.0.to_be_bytes();\n"));
            out.push_str(&format!("        self.0.comms_write_async(0x{:x}, &buf{}, {}).await?;\n", self.address, self.commsbuf_subscript(endian), self.access_proc_enum()));
            out.push_str(&format!("        Ok(())\n"));
            out.push_str(&format!("    }}\n"));

        }
        out.push_str(&format!("}}\n"));

        // Regval struct generation
        out.push_str(&format!("pub struct {}(pub {});\n", self.regval_struct_name(), self.regval_word_name()));
        out.push_str(&format!("impl {} {{\n", self.regval_struct_name()));
        out.push_str(&format!("    pub fn get(&self) -> {} {{\n", self.regval_word_name()));
        out.push_str(&format!("        self.0\n"));
        out.push_str(&format!("    }}\n"));
        if self.writable {
            out.push_str(&format!("    pub fn zero() -> Self {{\n"));
            out.push_str(&format!("         Self(0)\n"));
            out.push_str(&format!("    }}\n"));
        }
        for field in self.fields.iter() {
            out.push_str(&format!("    pub fn {}<'a>(&'a mut self) -> {}<'a> {{\n", field.method_name(), field.struct_name()));
            out.push_str(&format!("        {}(self)\n", field.struct_name()));
            out.push_str(&format!("    }}\n"));
        }
        out.push_str(&format!("}}\n"));

        // Field struct generation
        for field in self.fields.iter() {
            out.push_str(&format!("pub struct {}<'a>(pub &'a mut {});\n", field.struct_name(), self.regval_struct_name()));
            out.push_str(&format!("impl<'a> {}<'a> {{\n", field.struct_name()));
            match field.field_pos {
                FieldPos::Bit(bit_pos) => {
                    if self.readable {
                        out.push_str(&format!("    pub fn bit(&self) -> bool {{\n"));
                        out.push_str(&format!("        ((self.0.0 >> {}) & 1) != 0\n", bit_pos));
                        out.push_str(&format!("    }}\n"));
                        out.push_str(&format!("    pub fn bit_is_set(&self) -> bool {{\n"));
                        out.push_str(&format!("        self.bit()\n"));
                        out.push_str(&format!("    }}\n"));
                    }
                    if self.writable {
                        out.push_str(&format!("    pub fn assign(self, val: bool) -> &'a mut {} {{\n", self.regval_struct_name()));
                        out.push_str(&format!("        self.0.0 &= !(1 << {});\n", bit_pos));
                        out.push_str(&format!("        self.0.0 |= !(!(val as {}) << {});\n", self.regval_word_name(), bit_pos));
                        out.push_str(&format!("        self.0\n"));
                        out.push_str(&format!("    }}\n"));
                        out.push_str(&format!("    pub fn set_bit(self) -> &'a mut {} {{\n", self.regval_struct_name()));
                        out.push_str(&format!("        self.assign(true)\n"));
                        out.push_str(&format!("    }}\n"));
                        out.push_str(&format!("    pub fn clear_bit(self) -> &'a mut {} {{\n", self.regval_struct_name()));
                        out.push_str(&format!("        self.assign(false)\n"));
                        out.push_str(&format!("    }}\n"));
                    }
                }
                FieldPos::Field(high, low) => {
                    let field_len = high - low + 1;
                    if self.readable {
                        out.push_str(&format!("    pub fn bits(&self) -> {} {{\n", field.field_pos.fieldpos_word()));
                        if field_len == self.regval_word_size() * 8 {
                            out.push_str(&format!("        self.0.0\n"));
                        } else {
                            out.push_str(&format!("        ((self.0.0 >> {}) & !(!0 << {})) as {}\n", low, field_len, field.field_pos.fieldpos_word()));
                        }
                        out.push_str(&format!("    }}\n"));
                    }
                    if self.writable {
                        out.push_str(&format!("    pub fn set(self, val: {}) -> &'a mut {} {{\n", field.field_pos.fieldpos_word(), self.regval_struct_name()));
                        if field_len == self.regval_word_size() * 8 {
                            out.push_str(&format!("        self.0.0 = val;\n"));
                        } else {
                            out.push_str(&format!("        self.0.0 &= !(!(!0 << {}) << {});\n", field_len, low));
                            out.push_str(&format!("        self.0.0 |= ((val as {}) & !(!0 << {})) << {};\n", self.regval_word_name(), field_len, low));

                        }
                        out.push_str(&format!("        self.0\n"));
                        out.push_str(&format!("    }}\n"));
                    }
                }
            }
            out.push_str(&format!("}}\n"));
        }
        out
    }
}