Enable tasks execution and syscalls

1 files changed, 11 insertions, 4 deletions

diff --git a/src/utils/gdt.c b/src/utils/gdt.c
index fd86f5f..c380283 100644
--- a/src/utils/gdt.c
+++ b/src/utils/gdt.c
@@ -5,7 +5,7 @@ struct GDT_REGISTER GDTR = { 0, 0 };
 GDT_TSS TSS;
 
 void gdt_memcpy(){
-  GDTR.limit=8*8; // Each entry is 8 bytes and 8 entries
+  GDTR.limit=8*GDT_MAX_ENTRIES; // Each entry is 8 bytes and 8 entries
   GDTR.base=0x800;
   gdt_write_entry((GDT_ENTRY){0,0,0,0},0); // First one must be null
 
@@ -60,12 +60,10 @@ void gdt_memcpy(){
   // Init TSS segment
   TSS.t_reserved=0;
   TSS.io_map=0;
-  TSS.ss0=0x18;
-  TSS.esp0=0x50000;
 
   GDT_ENTRY tss_desc;
   tss_desc.base=(u32)&TSS; // Not used in stack descriptor
-  tss_desc.limit=0x68;  // Define how much entry it can contains
+  tss_desc.limit=0x68;  // Define how much bytes it occupies
   tss_desc.flags=0;
   tss_desc.access=0x89 | GDT_PRVL_3; // Note that 0x89 is specific to TSS!
   gdt_write_entry(tss_desc, 7);
@@ -89,3 +87,12 @@ void gdt_write_entry(GDT_ENTRY entry, u32 id){
   // Copy descriptor into memory
   memcpy(descriptor,(void*)GDTR.base+8*id,8); // Each entry is 64 bits (8 bytes)
 }
+
+int gdt_user_ds_base(){
+  char *addr=(char*)GDTR.base+48;
+  int *base0_15=(int*)addr+2;
+  int *base16_31=(int*)addr+7;
+  int base0_15_content=*base0_15 & 0xFFFF;
+  int base16_21_content=*base16_31 & 0xFFFF;
+  return(base16_21_content<<16 & base0_15_content);
+}
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