jump to physical address of kernel works, kernel prints HI to COM1

build.bat

@@ -16,7 +16,7 @@ rd /s /q image
 mkdir image\EFI\BOOT
 copy kernel\boot\bootx64.efi image\EFI\BOOT\BOOTX64.EFI
 copy kernel\kernel64.bin image\EFI\KERNEL64.BIN
-qemu-system-x86_64 -cpu qemu64 -bios OVMF.fd -drive driver=vvfat,rw=on,dir=image\
+qemu-system-x86_64 -cpu qemu64 -bios OVMF.fd -drive driver=vvfat,rw=on,dir=image\ -serial stdio
 goto :eof
 
 :error

kernel/boot/bootx64.asm

@@ -23,8 +23,6 @@ include 'uefi64.inc'
 
 MEMORY_MAP_SIZE = 0x10000 ; NOTE: can be bigger?
 
-VIRT_KERNEL_BASE = 0xFFFFFFFF80000000
-
 ; linux/arch/x86/include/uapi/asm/e820.h
 E820_RAM       = 1
 E820_RESERVED  = 2
@@ -396,8 +394,19 @@ proc main _efi_handle, _efi_table
         cmp     rcx, [kernel_image_phys_end]
         jb      .fill_p1 
 
+        ; causes fault and reboots. maybe i need exitbootservices first? maybe paging structures incorrect
+        ; mov     rax, table_p4
+        ; mov     cr3, rax
+
+        ; TODO ExitBootServices here
+
+        mov     rax, [kernel_image_phys_base]
+        mov     rax, [rax + KERNEL64_HEADER.entry_point_offset]
+        add     rax, [kernel_image_phys_base] ; jump to phys kernel for now
+        ; add     rax, VIRT_KERNEL_BASE
+        jmp     rax
+
         ; TODO
-        ;; put phys start / end into kernel header
         ;; map [kernel_phys_start; kernel_phys_end) to 0xFFFFFFFF80000000
         ;; (~~fill paging tables~~, ExitBootServices and switch to the new PML4), set kernel rsp, jmp to k64_entry
         ;; NOTE: dont allocate after getting memmap bc uefi allocations change the memmap. => perform GetMemoryMap last of all..

kernel/const.inc

@@ -1,3 +1,13 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;                                                              ;;
+;; Copyright (C) KolibriOS team 2025-2025. All rights reserved. ;;
+;; Distributed under terms of the GNU General Public License v2 ;;
+;;                                                              ;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+
+VIRT_KERNEL_BASE = 0xFFFFFFFF80000000
+
 struct DQ
         union
                 lo    dd ?

kernel/kernel64.asm

@@ -7,39 +7,73 @@
 
 use64
 
-VIRT_KERNEL_BASE = 0xFFFFFFFF80000000
+include 'struct.inc'
-DEFAULT_STACK_SIZE = 8192
+include 'proc64.inc'
+include 'const.inc'
 
 org VIRT_KERNEL_BASE
 
+DEFAULT_STACK_SIZE = 4096*2
+
 dq 'KERNEL64' ; magic
 dq k64_entry - VIRT_KERNEL_BASE ; entry point's offset from base where it loaded
 dq DEFAULT_STACK_SIZE ; how many bytes of stack we need
 kernel_phys_start dq 0 ; bootloader will put here phys addr where it loaded kernel
 kernel_phys_end dq 0 ; and phys end addr (including stack ofc)
 
+PORT_COM1 = 0x3f8
+
+macro outb port_, byte_  {
+        mov     dx, port_
+        mov     al, byte_
+        out     dx, al
+}
+
+macro inb port_ {
+        mov     dx, port_
+        in      al, dx
+}
+
+; rcx - byte to write
+; uses rdx
+write_com1:
+@@:
+        inb     PORT_COM1 + 5
+        and     al, 0x20
+        test    al, al
+        jz      @b
+        outb    PORT_COM1, cl
+        ret
+
+
 ; 64 bit kernel entry point
 k64_entry:
-        ;; NOTE! oops addresses are incorrect
+        ; init com port:
-        pop     qword [qword puthex_ptr - VIRT_KERNEL_BASE]
+        outb    PORT_COM1 + 1, 0x00
-        pop     qword [qword putstr_ptr - VIRT_KERNEL_BASE]
+        outb    PORT_COM1 + 3, 0x80
+        outb    PORT_COM1 + 0, 0x03
+        outb    PORT_COM1 + 1, 0x00
+        outb    PORT_COM1 + 3, 0x03
+        outb    PORT_COM1 + 2, 0xC7
+        outb    PORT_COM1 + 4, 0x0B
+        outb    PORT_COM1 + 4, 0x1E
+        outb    PORT_COM1 + 0, 0xAE
+        ; check if serial is faulty (i.e: not same byte as sent)
+        inb     PORT_COM1 + 0
+        cmp     al, 0xAE
+        jnz     .abyss
+        ; set port in normal operation mode
+        ; (not-loopback with IRQs enabled and OUT#1 and OUT#2 bits enabled)
+        outb    PORT_COM1 + 4, 0x0F
 
-        sub     rsp, 0x20
+        ;; try write some chars
-        mov     rcx, kmsg_hello - VIRT_KERNEL_BASE
+        mov     rcx, 'H'
-        call    qword [qword putstr_ptr - VIRT_KERNEL_BASE]
+        call    write_com1
-        add     rsp, 0x20
+        mov     rcx, 'I'
-
+        call    write_com1
-        sub     rsp, 0x20
-        mov     rcx, kmsg_ripis - VIRT_KERNEL_BASE
-        call    qword [qword putstr_ptr - VIRT_KERNEL_BASE]
-        add     rsp, 0x20
-
-        sub     rsp, 0x20
-        lea     rcx, [rip]
-        call    qword [qword puthex_ptr - VIRT_KERNEL_BASE]
-        add     rsp, 0x20
 
         jmp     $
+.abyss:
 
 
 kmsg_hello      db 'Hello from KERNEL',13,10,0