Share commo DMA related code for use with SPU

include/PSX/File/file_processor_helper.hpp

@@ -1,6 +1,7 @@
 #pragma once
 #include "Processor/file_processor.hpp"
 #include "cd_file_types.hpp"
+#include <limits.hpp>
 
 namespace JabyEngine {
     namespace FileProcessor {
@@ -18,6 +19,54 @@ namespace JabyEngine {
                 config.process_routine = reinterpret_cast<State::ProcessRoutine>(process_routine);
                 return process_routine(config, state);
             }
+
+            namespace DMA {
+                using words_t = size_t;
+
+                struct WordsReady {
+                    uint32_t words_to_use;
+                    bool     is_last;
+
+                    static constexpr WordsReady calculate(const State::Configuration& config, words_t words_left) {
+                        const auto config_data_words = (config.data_bytes/sizeof(uint32_t));
+                        const auto words_to_use      = (config_data_words > words_left) ? words_left : config_data_words;
+            
+                        return {
+                            .words_to_use = words_to_use,
+                            .is_last      = words_to_use == words_left
+                        };
+                    }
+                };
+
+                template<typename T>
+                static words_t send_words(words_t words_to_send, bool send_all) {
+                    auto blocks_to_send = words_to_send/16;
+                    while(blocks_to_send > 0) {
+                        const auto block_send = (blocks_to_send > UI16_MAX) ? UI16_MAX : blocks_to_send;
+
+                        // Send data!
+                        T::wait();
+                        T::Receive::start(blocks_to_send);
+                        blocks_to_send -= block_send;
+                    }
+
+                    if(send_all) {
+                        const auto last_words_to_send = (words_to_send & 0b1111);
+                        if(last_words_to_send > 0) {
+                            T::wait();
+                            T::Receive::start(1, last_words_to_send);
+                        }
+                        
+                        T::wait();
+                        T::end();
+                        return words_to_send;
+                    }
+
+                    else {
+                        return (words_to_send & ~0b1111);
+                    }
+                }
+            }  
         }
     }
 }