From 093969301e8ff8a40650285aef10a32f31c1c558 Mon Sep 17 00:00:00 2001
From: Thomas Oltmann <thomas.oltmann.hhg@gmail.com>
Date: Wed, 9 Jul 2025 19:29:27 +0200
Subject: [PATCH] Trying to debug failing TFTP open

---
 lboot.S | 75 +++++++++++++++++++++++++++++++++------------------------
 1 file changed, 44 insertions(+), 31 deletions(-)

diff --git a/lboot.S b/lboot.S
index 0b734b0..88bf871 100644
--- a/lboot.S
+++ b/lboot.S
@@ -89,6 +89,8 @@ _start:     cli
             add         $12, %sp
             mov         tx_buf+20, %eax
             mov         %eax, server_ip
+            mov         tx_buf+24, %eax
+            mov         %eax, gateway_ip
 
             mov         $msg_unreal, %si
             call        print
@@ -323,16 +325,30 @@ tftp_open:  push        %ecx
             push        %bp
             mov         %sp, %bp
 
+            mov         %esi, %ebx
+
+            mov         $msg_topen, %si
+            call        print
+
             push        $PACKET_SIZE
             push        $69<<8
             mov         $128, %ecx
-            sub         %cx,  %sp
+            sub         %cx, %sp
             mov         %ss,  %edi
             shl         $4,   %edi
             add         %esp, %edi
+            xor         %ax, %ax
+            cld
+            addr32 rep stosb
+            mov         %ebx, %esi
+            mov         $6, %ecx
+            mov         %ss,  %edi
+            shl         $4,   %edi
+            add         %esp, %edi
+            cld
             addr32 rep movsb
-            push        $0
-            push        $0
+            push        gateway_ip+2
+            push        gateway_ip
             push        server_ip+2
             push        server_ip
             push        $0
@@ -348,6 +364,9 @@ tftp_open:  push        %ecx
 tftp_close: push        %bp
             mov         %sp, %bp
             
+            mov         $msg_tclose, %si
+            call        print
+
             push        $0
             pxe_call    PXE_TFTP_CLOSE
 
@@ -359,6 +378,9 @@ tftp_read:  push        %ebx
             push        %bp
             mov         %sp, %bp
 
+            mov         $msg_tread, %si
+            call        print
+
             push        %cs
             push        $tx_buf
             push        $0
@@ -377,7 +399,14 @@ out_of_mem: mov         $msg_memerr, %si
             jmp         hang
 
             // print: print NUL-terminated string pointed to by SI
-print:      xor         %bx, %bx
+print:      push        %eax
+            push        %ebx
+            push        %edx
+            push        %esi
+            push        %bp
+            mov         %sp, %bp
+
+            xor         %bx, %bx
 
 _prnext:    mov         $COM1+5, %dx
             inb         %dx, %al
@@ -395,7 +424,12 @@ _prnext:    mov         $COM1+5, %dx
             int         $0x10
             jmp         _prnext
 
-_prdone:    ret
+_prdone:    leave
+            pop         %esi
+            pop         %edx
+            pop         %ebx
+            pop         %eax
+            ret
 
             // long: Enter long mode
 long:       
@@ -434,33 +468,8 @@ long:
 hang:       hlt
             jmp         hang
 
-_pcerr:     push        %cx
-
-            mov         $msg_pcerr, %si
+_pcerr:     mov         $msg_pcerr, %si
             call        print
-
-            pop         %cx
-            push        %cx
-
-            xor         %bx, %bx
-            mov         %ch, %bl
-            mov         hex_digits(%bx), %bl
-            mov         %bx, tx_buf
-            mov         $tx_buf, %si
-            call        print
-
-            pop         %cx
-            push        %cx
-
-            xor         %bx, %bx
-            mov         %cl, %bl
-            mov         hex_digits(%bx), %bl
-            mov         %bx, tx_buf
-            mov         $tx_buf, %si
-            call        print
-
-            pop         %cx
-
             jmp         hang
 
             // gdt16: Protected mode / Unreal mode 16-bit GDT
@@ -522,11 +531,15 @@ msg_long:   .asciz      " * Long Mode\r\n"
 msg_pserr:  .asciz      "panic: Missing !PXE structure.\r\n"
 msg_pcerr:  .asciz      "panic: PXE call failed.\r\n"
 msg_memerr: .asciz      "panic: Out of heap space.\r\n"
+msg_topen:  .asciz      "tftp_open\r\n"
+msg_tclose: .asciz      "tftp_close\r\n"
+msg_tread:  .asciz      "tftp_read\r\n"
 
 fn_initrd:  .asciz      "initrd"
 
 pxe_api:    .long       0
 server_ip:  .space      4
+gateway_ip: .space      4
 
 heap_ptr:   .long       0
 heap_end:   .long       0