From 8ff10c938c93996df45d518f5d423c8ce9c6877f Mon Sep 17 00:00:00 2001
From: Mathieu Maret <mathieu.maret@gmail.com>
Date: Mon, 18 Oct 2021 20:39:08 +0200
Subject: [PATCH] Improve print information from mbi

---
 core/main.c | 47 +++++++++++++++++++++++++++++++----------------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/core/main.c b/core/main.c
index e173311..1f0415f 100644
--- a/core/main.c
+++ b/core/main.c
@@ -53,6 +53,7 @@ void kmain(unsigned long magic, unsigned long addr)
     irqSetup();
     pitSetup(HZ);
 
+    // https://www.gnu.org/software/grub/manual/multiboot/multiboot.html#Boot-information-format
     if (magic == MULTIBOOT_BOOTLOADER_MAGIC) { // Get loaded by Grub with mutliboot version 1
         multiboot_info_t *mbi = (multiboot_info_t *)addr;
         /* Are mem_* valid? */
@@ -63,7 +64,34 @@ void kmain(unsigned long magic, unsigned long addr)
 
         /* Is boot_device valid? */
         if (CHECK_FLAG(mbi->flags, 1)) {
-            printf("boot_device = %d\n", mbi->boot_device);
+            int disk = mbi->boot_device >> 24 & 0xff;
+            int part1 = mbi->boot_device >> 16 & 0xff;
+            int part2 = mbi->boot_device >> 8 & 0xff;
+            int part3 = mbi->boot_device & 0xff;
+            printf("boot_device = 0x%x (0x0 for floppy 0x80 for disk) part %d %d %d\n", disk, part1, part2, part3);
+        }
+
+        if (CHECK_FLAG(mbi->flags, 3)) {
+            if (mbi->mods_count > 0) {
+                multiboot_module_t *mod;
+                uint32_t i;
+
+                printf("mods_count = %d, mods_addr = 0x%x\n", (int)mbi->mods_count,
+                       (int)mbi->mods_addr);
+                for (i = 0, mod = (multiboot_module_t *)mbi->mods_addr; i < mbi->mods_count;
+                     i++, mod++)
+                    printf(" mod_start = 0x%x, mod_end = 0x%x, cmdline = %s\n",
+                           (unsigned)mod->mod_start, (unsigned)mod->mod_end,
+                           (char *)mod->cmdline);
+            }
+        }
+
+        if (CHECK_FLAG(mbi->flags, 6)) {
+            memMapAvailable = 1;
+        }
+
+        if (CHECK_FLAG(mbi->flags, 9)) {
+            printf("Loaded by %s. ", mbi->boot_loader_name);
         }
 
         /* Is the command line passed? */
@@ -71,22 +99,9 @@ void kmain(unsigned long magic, unsigned long addr)
             printf("cmdline = %s\n", (char *)mbi->cmdline);
         }
 
-        if (CHECK_FLAG(mbi->flags, 3)) {
-            multiboot_module_t *mod;
-            uint32_t i;
-
-            printf("mods_count = %d, mods_addr = 0x%x\n", (int)mbi->mods_count,
-                   (int)mbi->mods_addr);
-            for (i = 0, mod = (multiboot_module_t *)mbi->mods_addr; i < mbi->mods_count;
-                 i++, mod++)
-                printf(" mod_start = 0x%x, mod_end = 0x%x, cmdline = %s\n",
-                       (unsigned)mod->mod_start, (unsigned)mod->mod_end, (char *)mod->cmdline);
+        if (CHECK_FLAG(mbi->flags, 12)) {
+            printf("Framebuffer from 0x%llx size (%dx%d) pitch %d bpp %d\n", mbi->framebuffer_addr, mbi->framebuffer_width, mbi->framebuffer_height, mbi->framebuffer_pitch, mbi->framebuffer_bpp);
         }
-
-        if (CHECK_FLAG(mbi->flags, 6)) {
-            memMapAvailable = 1;
-        }
-        printf("Framebuffer from 0x%llx size (%dx%d) pitch %d bpp %d\n", mbi->framebuffer_addr, mbi->framebuffer_width, mbi->framebuffer_height, mbi->framebuffer_pitch, mbi->framebuffer_bpp);
     }
 
     if (upperMemKB == 0) {