Add 1001 Card Cruncher packer strategy

Implement signature detection for 1001 CardCruncher ACM and v4 variants. Fix unpacker SYS address search fallback when PRG load address is below $0800. Add 1001 Card Cruncher test case and verify 100% equivalence against unp64.

Author: ricardoquesada

crates/regenerator2000-core/src/bin/unpacker_compare_all.rs

@@ -61,6 +61,7 @@ fn main() {
         "c64_soul_on_fire_unk.prg",
         "c64_gianna_sister_remix_badboy.tbc_multicompactor.prg",
         "c64_chiller.antiram_packer.prg",
+        "c64_323_ice_psm.1001_card_cruncher.prg",
     ];
 
     println!(

crates/regenerator2000-core/src/packers/card_cruncher.rs

@@ -0,0 +1,69 @@
+//! 1001 Card Cruncher strategy implementation.
+
+use super::simple::SimplePacker;
+use super::{Packer, PackerInfo};
+
+/// Detects 1001 Card Cruncher signature.
+#[must_use]
+pub fn detect(mem: &[u8], load_addr: u16) -> Option<Box<dyn Packer>> {
+    if mem.len() > 0x840 && load_addr <= 0x0801 {
+        // Variant 1: 1001 CardCruncher ACM
+        // Code at $080D / $080F: SEI; LDX #$F0; STX $01; LDA $src,X; STA $dst,X; DEX; BNE; JMP $0100
+        for q in [0x080D_usize, 0x080F_usize] {
+            if mem.len() > q + 17
+                && mem[q] == 0x78
+                && mem[q + 1] == 0xA2
+                && mem[q + 3] == 0x86
+                && mem[q + 4] == 0x01
+                && mem[q + 5] == 0xBD
+                && mem[q + 8] == 0x9D
+                && mem[q + 11] == 0xCA
+                && mem[q + 12] == 0xD0
+                && mem[q + 14] == 0x4C
+                && mem[q + 15] == 0x00
+                && mem[q + 16] == 0x01
+            {
+                let end_val = u16::from_le_bytes([mem[0x081E], mem[0x081F]]);
+                let entry_val = u16::from_le_bytes([mem[0x083F], mem[0x0840]]);
+                let end_addr = if end_val > load_addr {
+                    Some(end_val.saturating_sub(1))
+                } else {
+                    None
+                };
+
+                return Some(Box::new(SimplePacker::new(PackerInfo {
+                    name: "1001 CardCruncher ACM",
+                    dep_addr: Some(0x0100),
+                    start_addr: Some(0x0801),
+                    end_addr,
+                    entry_point: Some(entry_val),
+                    end_addr_ptr: None,
+                })));
+            }
+        }
+
+        // Variant 2: 1001 CardCruncher v4
+        // Code at $0815: STX $01; LDA $082A,Y; STA $FA99...
+        if mem.len() > 0x941
+            && mem[0x815] == 0x86
+            && mem[0x816] == 0x01
+            && mem[0x81A] == 0x2A
+            && mem[0x81B] == 0x08
+            && mem[0x81C] == 0x99
+            && mem[0x81D] == 0xFA
+        {
+            let end_val = u16::from_le_bytes([mem[0x82E], mem[0x82F]]);
+            let entry_val = u16::from_le_bytes([mem[0x940], mem[0x941]]);
+
+            return Some(Box::new(SimplePacker::new(PackerInfo {
+                name: "1001 CardCruncher v4",
+                dep_addr: Some(0x0100),
+                start_addr: Some(0x0801),
+                end_addr: Some(end_val),
+                entry_point: Some(entry_val),
+                end_addr_ptr: None,
+            })));
+        }
+    }
+    None
+}

crates/regenerator2000-core/src/packers/mod.rs

@@ -4,6 +4,7 @@ pub mod action_replay;
 pub mod alz64;
 pub mod antiram;
 pub mod byteboozer;
+pub mod card_cruncher;
 pub mod ccs;
 pub mod cruel_cruncher;
 pub mod dali;
@@ -104,6 +105,9 @@ pub fn detect_packer(mem: &[u8], load_addr: u16, load_end: u16) -> Option<Box<dy
     if let Some(p) = time_cruncher::detect(mem) {
         return Some(p);
     }
+    if let Some(p) = card_cruncher::detect(mem, load_addr) {
+        return Some(p);
+    }
     if let Some(p) = mc_cracken::detect(mem) {
         return Some(p);
     }

crates/regenerator2000-core/src/unpacker.rs

@@ -1032,7 +1032,9 @@ pub fn unpack(
     let entry = if let Some(forced) = config.forced_entry {
         forced
     } else {
-        find_sys_address(&memory.mem, basic_start).ok_or(UnpackError::NoEntryPoint)?
+        find_sys_address(&memory.mem, basic_start)
+            .or_else(|| find_sys_address(&memory.mem, 0x0801))
+            .ok_or(UnpackError::NoEntryPoint)?
     };
 
     let ret_addr = config
@@ -1686,6 +1688,16 @@ mod tests {
                 exp_end: 0xF732,
                 exp_entry: 0xE000,
                 exp_dep: Some(0x005E),
+                exp_packer: None,
+                max_instructions: None,
+            },
+            KnownUnpackCase {
+                file: "c64_323_ice_psm.1001_card_cruncher.prg",
+                exp_start: 0x0801,
+                exp_end: 0x319C,
+                exp_entry: 0x3197,
+                exp_dep: Some(0x0100),
+                exp_packer: Some("1001 CardCruncher ACM"),
                 max_instructions: None,
             },
         ];