Display BIOS date correctly

examples/PoolBox/application/src/Overlay/BIOSInfo/bios_info.cpp

@@ -59,7 +59,7 @@ namespace BIOSInfo {
         font_sliders[0] = FontSlider::create_for(FontWriter::BIOSFont::Info, result.kernel_maker);
         font_sliders[1] = FontSlider::create_for(FontWriter::BIOSFont::Info, result.gui_version);
         border_tiles[0].concat(border_tiles[1]);
-        return SysCall::get_bios_version();
+        return result;
     }
 
     static bool update_or_exit(const SysCall::BIOSVersion& bios_version) {
@@ -78,7 +78,7 @@ namespace BIOSInfo {
         }
 
         auto cursor = FontWriter::update(TextOffset);
-        FontWriter::bios_font_writer.write(cursor, "BIOS INFORMATION\n----------------\nDate:\n%X\nKernel-Maker:\n", bios_version.date_bcd);
+        FontWriter::bios_font_writer.write(cursor, "BIOS INFORMATION\n----------------\nDate (day/month/year):\n%i/%i/%i\nKernel-Maker:\n", bios_version.date.day, bios_version.date.month, bios_version.date.year);
         
         const auto old_pos_x = cursor.pos.x;
         FontWriter::bios_font_writer.write(move_cursor(cursor, font_sliders[0].count, old_pos_x), "%s\n", bios_version.kernel_maker);

include/PSX/Auxiliary/math_helper.hpp

@@ -1,7 +1,18 @@
 #pragma once
 #include "types.hpp"
+#include <stddef.h>
 
 namespace JabyEngine {
+    template<typename T>
+    static constexpr T pow(T base, T power) {
+        T result = base;
+        while(power > 1) {
+            result = result*base;
+            power--;
+        }
+        return result;
+    }
+
     template<typename T>
     static constexpr pair<T, T> div_and_mod(T value, T div) {
         const auto result = value/div;
@@ -12,4 +23,15 @@ namespace JabyEngine {
         const auto [tenth, rest] = div_and_mod(value, static_cast<uint8_t>(10));
         return (tenth << 4 | rest);
     }
+
+    template<typename T>
+    static constexpr T from_bcd(T value) {
+        T result = 0;
+
+        for(size_t n = 1; n < pow(10u, sizeof(T)*2); n *= 10) {
+            result += (value & 0b1111)*n;
+            value = value >> 4;
+        }
+        return result;
+    }
 }

include/PSX/System/syscalls.hpp

@@ -56,7 +56,11 @@ namespace JabyEngine {
         #pragma pack(pop)
 
         struct BIOSVersion {
-            uint32_t    date_bcd;
+            struct {
+                uint8_t  day;
+                uint8_t  month;
+                uint16_t year;
+            } date;
             const char* kernel_maker;
             const char* gui_version;
         };

src/Library/src/System/syscall.cpp

@@ -1,3 +1,4 @@
+#include <PSX/Auxiliary/math_helper.hpp>
 #include <PSX/System/syscalls.hpp>
 
 namespace JabyEngine {
@@ -5,7 +6,11 @@ namespace JabyEngine {
         BIOSVersion get_bios_version() {
             BIOSVersion version;
 
-            version.date_bcd     = *reinterpret_cast<uint32_t*>(0xBFC00100);
+            const auto date_bcd = *reinterpret_cast<uint32_t*>(0xBFC00100);
+
+            version.date.day     = from_bcd(static_cast<uint8_t>(date_bcd & 0xFF));
+            version.date.month   = from_bcd(static_cast<uint8_t>((date_bcd >> 8) & 0xFF));
+            version.date.year    = from_bcd(static_cast<uint16_t>(date_bcd >> 16));
             version.kernel_maker = reinterpret_cast<const char*>(0xBFC00108);
             version.gui_version  = reinterpret_cast<const char*>(0xBFC7FF32);
             return version;