Add support for the CP/M CMD file module format

3 files changed, 68 insertions, 0 deletions

diff --git a/src/bin/tq.rs b/src/bin/tq.rs
index b27f702..ffbc330 100644
--- a/src/bin/tq.rs
+++ b/src/bin/tq.rs
@@ -172,6 +172,7 @@ Created by Ben Bridle.
 
     if !dry_run {
         let result = match format {
+            Format::Cmd => format_cmd(&segments),
             Format::Debug => format_debug(&segments),
             Format::Inhx => format_inhx(&segments),
             Format::Inhx32 => format_inhx32(&segments),
diff --git a/src/formats/cmd.rs b/src/formats/cmd.rs
new file mode 100644
index 0000000..2ff2097
--- /dev/null
+++ b/src/formats/cmd.rs
@@ -0,0 +1,54 @@
+// CP/M CMD format, also the TRS-80 Load Module Format (LMF)
+// https://en.wikipedia.org/wiki/CMD_file_(CP/M)
+// https://www.tim-mann.org/trs80/doc/ldosq1-4.pdf (page 43)
+use crate::*;
+
+
+pub fn format_cmd(segments: &[Segment]) -> Result<Vec<u8>, FormatError> {
+    let mut records = Vec::new();
+    let mut address;
+    for segment in segments {
+        address = segment.address;
+        for chunk in segment.words.chunks(16) {
+            records.push(data_record(chunk, address)?);
+            address += 16;
+        }
+    }
+    let start_address = segments.first().map(|s| s.address).unwrap_or(0);
+    records.push(terminating_record(start_address)?);
+
+    let mut output = String::new();
+    for record in records {
+        output.push_str(&record.to_string_plain());
+    }
+    return Ok(output.into_bytes());
+}
+
+fn data_record(words: &[Tracked<Word>], address: usize) -> Result<InhxRecord, FormatError> {
+    let Ok(address) = u16::try_from(address) else {
+        return Err(FormatError::AddressTooLarge(u16::MAX as usize, address));
+    };
+    let mut record = InhxRecord::new();
+    record.byte(0x01);
+    let data_bytes = words.len() as u8;
+    record.byte(data_bytes.wrapping_add(2));
+    record.le_double(address);
+    for word in words {
+        if word.value.width > 8 {
+            return Err(FormatError::WordTooWide(8, word.width, word.source.clone()));
+        }
+        record.byte(word.value.value as u8);
+    }
+    return Ok(record);
+}
+
+fn terminating_record(address: usize) -> Result<InhxRecord, FormatError> {
+    let Ok(address) = u16::try_from(address) else {
+        return Err(FormatError::AddressTooLarge(u16::MAX as usize, address));
+    };
+    let mut record = InhxRecord::new();
+    record.byte(0x02);
+    record.byte(0x02);
+    record.le_double(address);
+    return Ok(record);
+}
diff --git a/src/formats/mod.rs b/src/formats/mod.rs
index a77bd72..105207c 100644
--- a/src/formats/mod.rs
+++ b/src/formats/mod.rs
@@ -1,8 +1,10 @@
+mod cmd;
 mod inhx;
 mod inhx32;
 mod raw;
 mod debug;
 
+pub use cmd::*;
 pub use inhx::*;
 pub use inhx32::*;
 pub use raw::*;
@@ -15,6 +17,7 @@ use log::*;
 
 #[derive(Clone, Copy, PartialEq)]
 pub enum Format {
+    Cmd,
     Debug,
     Inhx,
     Inhx32,
@@ -25,6 +28,7 @@ pub enum Format {
 impl Format {
     pub fn from_str(string: &str) -> Self {
         match string {
+            "cmd" => Self::Cmd,
             "debug" => Self::Debug,
             "inhx" => Self::Inhx,
             "inhx32" => Self::Inhx32,
@@ -38,6 +42,7 @@ impl Format {
 impl std::fmt::Display for Format {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
         let string = match self {
+            Self::Cmd => "cmd",
             Self::Debug => "debug",
             Self::Inhx => "inhx",
             Self::Inhx32 => "inhx32",
@@ -112,6 +117,14 @@ impl InhxRecord {
         }
         format!(":{output}{checksum:0>2X}\n")
     }
+
+    pub fn to_string_plain(self) -> String {
+        let mut output = String::new();
+        for byte in &self.bytes {
+            output.push_str(&format!("{byte:0>2X}"));
+        }
+        format!("{output}\n")
+    }
 }