From 9cbecc16897cec84407395d45f3ef95c38419ac8 Mon Sep 17 00:00:00 2001
From: xamidev <xamidev@riseup.net>
Date: Sat, 10 Jan 2026 11:04:08 +0100
Subject: [PATCH] GP Fault handler

---
 src/idt/idt.c      | 29 ++++++++++++++++++++++++++++-
 src/io/term/term.c |  9 +++++++--
 2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/src/idt/idt.c b/src/idt/idt.c
index af05f63..7c59c64 100644
--- a/src/idt/idt.c
+++ b/src/idt/idt.c
@@ -4,6 +4,7 @@
 #include "io/serial/serial.h"
 #include "io/kbd/ps2.h"
 #include <kernel.h>
+#include <stdbool.h>
 
 struct interrupt_descriptor idt[256];
 struct idtr idt_reg;
@@ -85,6 +86,32 @@ static void page_fault_handler(struct cpu_status_t* ctx)
     panic(ctx);
 }
 
+static void gp_fault_handler(struct cpu_status_t* ctx)
+{
+    DEBUG("\x1b[38;5;231mGeneral Protection Fault at rip=0x%p, err=%u (%s)\x1b[0m",
+    ctx->iret_rip,
+    ctx->error_code,
+    (ctx->error_code == 0) ? "NOT_SEGMENT_RELATED" : "SEGMENT_RELATED");
+
+    // Segment-related
+    if (ctx->error_code != 0)
+    {
+        bool is_external = CHECK_BIT(ctx->error_code, 0);
+        // is it IDT, GDT, LDT?
+        uint8_t table = ctx->error_code & 0x6; // 0b110 (isolate table)
+        uint16_t index = ctx->error_code & 0xFFF8; // 13*1 1111111111111 + 000 = 1111111111111000
+    
+        char* table_names[4] = {"GDT", "IDT", "LDT", "IDT"};
+
+        DEBUG("\x1b[38;5;231m%s in %s index %u\x1b[0m",
+        is_external ? "EXTERNAL" : "INTERNAL",
+        table_names[table],
+        index);
+    }
+
+    panic(ctx);
+}
+
 struct cpu_status_t* interrupt_dispatch(struct cpu_status_t* context)
 {
     switch(context->vector_number)
@@ -129,7 +156,7 @@ struct cpu_status_t* interrupt_dispatch(struct cpu_status_t* context)
             DEBUG("Stack-Segment Fault!");
             break;
         case 13:
-            DEBUG("General Protection Fault!");
+            gp_fault_handler(context);
             break;
         case 14:
             // Better debugging for page faults...
diff --git a/src/io/term/term.c b/src/io/term/term.c
index 2666725..6ecb5b9 100644
--- a/src/io/term/term.c
+++ b/src/io/term/term.c
@@ -46,7 +46,7 @@ int term_init()
 	{
 		fb = boot_ctx.fb->address;
 		framebuffer = boot_ctx.fb;
-		DEBUG("terminal initialized");
+		DEBUG("terminal initialized, fb=0x%p (width=%u height=%u pitch=%u bpp=%u)", fb, framebuffer->width, framebuffer->height, framebuffer->pitch, framebuffer->bpp);
 		return 0;
 	}
 	return -ENOMEM;
@@ -102,7 +102,12 @@ void term_scroll()
 	const size_t screen_rows = framebuffer->height;
 
 	// Move framebuffer up by one text row 
-	memmove(fb, fb + row_height * row_bytes, (screen_rows - row_height) * row_bytes);
+	//memmove(fb, fb + row_height * row_bytes, (screen_rows - row_height) * row_bytes);
+
+	for (size_t i = 0; i < (screen_rows - row_height) * row_bytes; i++)
+	{
+		fb[i] = fb[i + row_height * row_bytes];
+	}
 
 	// Clear last text row
 	size_t clear_start = (screen_rows - row_height) * row_bytes;