readrom: accept ranges for the --disassemble flag

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>

2 files changed, 20 insertions, 5 deletions

diff --git a/crates/readrom/README.md b/crates/readrom/README.md
index a1175fe..050b2d6 100644
--- a/crates/readrom/README.md
+++ b/crates/readrom/README.md
@@ -31,7 +31,19 @@ $A2F8:	24 20		bit $20
 
 Note that hexadecimal values can also be formatted like this `0xa2fb` or simply
 `a2fb`, whatever feels more convenient to use. In any case, they should be
-written as a 16-bit address.
+written as a 16-bit address. This flag also accepts ranges. Hence, we can also
+try the following:
+
+```
+$ readrom -d '$a2f8-$a300' jetpac.NTSC.nes
+# => output
+$A2F8:	24 20		bit $20
+$A2FA:	30 01		bmi $01
+$A2FC:	40		rti
+$A2FD:	48		pha
+$A2FE:	8A		txa
+$A2FF:	48		pha
+```
 
 All of that being said, poking for addresses can be tedious. That's why you can
 also pass names that you already know. For that, you will need to also pass the
@@ -168,6 +180,7 @@ Then:
 
 ```
 $ readrom -d nmi -n .nasm/ --mmc "kind=mmc3; prg_rom_mode=0; r6=0; r7=1" blink.nes
+# => output
 $E138:	24 20		bit $20
 $E13A:	10 2A		bpl @next
 $E13C:	48		pha
diff --git a/crates/readrom/src/main.rs b/crates/readrom/src/main.rs
index d3701d0..81b7e09 100644
--- a/crates/readrom/src/main.rs
+++ b/crates/readrom/src/main.rs
@@ -457,10 +457,12 @@ fn do_disassemble(
     }
 
     // If this is just a numeric value, take it as is.
-    if let Some(address) = address
-        && let Some(start) = parse_hex_value(address)
-    {
-        return print_range(bytes, start, None, memories, addresses, raw, None);
+    if let Some(address) = address {
+        let (start_addr, end_addr) = address.split_once('-').unwrap_or((address, ""));
+        if let Some(start) = parse_hex_value(start_addr) {
+            let end = parse_hex_value(end_addr);
+            return print_range(bytes, start, end, memories, addresses, raw, None);
+        }
     }
 
     // Otherwise, print the full range if possible.