From 17d6ca5329184f78ddaeff66548635ed207fd57e Mon Sep 17 00:00:00 2001
From: Jaby <fenir50@web.de>
Date: Wed, 13 Dec 2023 19:46:34 -0500
Subject: [PATCH] Load a BIOS font

---
 include/PSX/System/syscalls.hpp           | 15 +++++++++++----
 src/Library/src/BootLoader/start_boot.cpp | 21 +++++++++++++++++++++
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/include/PSX/System/syscalls.hpp b/include/PSX/System/syscalls.hpp
index f3b76916..00234cdd 100644
--- a/include/PSX/System/syscalls.hpp
+++ b/include/PSX/System/syscalls.hpp
@@ -148,18 +148,25 @@ namespace JabyEngine {
             return __syscall_function_cast(Table_B, uint32_t(*)(uint32_t))(event);
         }
 
-        static __always_inline int TestEvent(uint32_t event) {
+        static __always_inline int32_t TestEvent(uint32_t event) {
             register uint32_t FuncID asm("t1") = 0x0B;
             
             __asm__ volatile("" : "=r"(FuncID) : "r"(FuncID));
-            return __syscall_function_cast(Table_B, int (*)(uint32_t))(event);
+            return __syscall_function_cast(Table_B, int32_t (*)(uint32_t))(event);
         }
 
-        static __always_inline int EnableEvent(uint32_t event) {
+        static __always_inline int32_t EnableEvent(uint32_t event) {
             register uint32_t FuncID asm("t1") = 0x0C;
             
             __asm__ volatile("" : "=r"(FuncID) : "r"(FuncID));
-            return __syscall_function_cast(Table_B, int (*)(uint32_t))(event);
+            return __syscall_function_cast(Table_B, int32_t (*)(uint32_t))(event);
+        }
+
+        static __always_inline const uint16_t* Krom2RawAdd(uint16_t sjis_code) {
+            register uint32_t FuncID asm("t1") = 0x51;
+
+            __asm__ volatile("" : "=r"(FuncID) : "r"(FuncID));
+            return __syscall_function_cast(Table_B, const uint16_t* (*)(uint16_t))(sjis_code);
         }
 
         void printf(const char* txt, ...);
diff --git a/src/Library/src/BootLoader/start_boot.cpp b/src/Library/src/BootLoader/start_boot.cpp
index 2fd13df2..798815e0 100644
--- a/src/Library/src/BootLoader/start_boot.cpp
+++ b/src/Library/src/BootLoader/start_boot.cpp
@@ -3,6 +3,8 @@
 #include <PSX/System/IOPorts/dma_io.hpp>
 #include <stdio.h>
 
+#include <PSX/System/syscalls.hpp>
+
 extern "C" uint32_t __heap_start;
 extern "C" uint32_t __bss_start;
 extern "C" uint32_t __bss_end;
@@ -42,6 +44,24 @@ namespace JabyEngine {
             }
         }
     }
+
+    static void test_bios_font() {
+        static constexpr uint16_t SJIS = 0x83B5;
+
+        const auto*      font     = SysCall::Krom2RawAdd(SJIS);
+        const auto*const font_end = font + 16;
+        printf("Loading SJIS from @0x%p\n", font);
+        
+        for(; font < font_end; font++) {
+            const auto cur_char = __builtin_bswap16(*font);
+            for(uint16_t shift = 1 << 15; shift; shift = shift >> 1) {
+                printf(cur_char & shift ? "#" : " ");
+            }
+
+            printf("\n");
+        }
+    }
+
     void start() {
         static constexpr auto DebugX     = 0;
         static constexpr auto DebugY     = 0;
@@ -50,6 +70,7 @@ namespace JabyEngine {
         __debug_boot_print_at(GPU::Color24::White(), DebugX, DebugY, DebugScale, "Starting Planschbecken\n");
         printf("Heap starts @0x%p\n", &__heap_start);
         printf("BSS      from 0x%p to 0x%p (%u)\n", &__bss_start, &__bss_end, __bss_len);
+        test_bios_font();
         __debug_boot_print_at(GPU::Color24::Green(), DebugX, DebugY, DebugScale, "PLANSCHI from 0x%p to 0x%p\n", &__planschi_start, &__planschi_end);
         boot::Start::setup();