Printing a hex dump of the tftp_open cmd

lboot.S

@@ -59,6 +59,8 @@ _start:     cli
 
             call        init_com1
 
+            mov         $msg_start, %si
+            call        print
             mov         $msg_start, %si
             call        print
 
@@ -352,6 +354,13 @@ tftp_open:  push        %ecx
             push        server_ip+2
             push        server_ip
             push        $0
+
+            mov         %ss,  %esi
+            shl         $4,   %esi
+            add         %esp, %esi
+            mov         $128, %ecx
+            call        dump
+
             pxe_call    PXE_TFTP_OPEN
 
             leave
@@ -400,33 +409,91 @@ out_of_mem: mov         $msg_memerr, %si
 
             // print: print NUL-terminated string pointed to by SI
 print:      push        %eax
+            push        %si
+            push        %bp
+            mov         %sp, %bp
+1:          lodsb
+            or          %al, %al
+            jz          2f
+            call        printch
+            jmp         1b
+2:          leave
+            pop         %si
+            pop         %eax
+            ret
+
+printch:    push        %eax
             push        %ebx
             push        %edx
+            push        %ebp
+
+            mov         %ax, %bx
+
+1:          mov         $COM1+5, %dx
+            inb         %dx, %al
+            test        $0x20, %al
+            jz          1b
+
+            mov         %bx, %ax
+
+            mov         $COM1, %dx
+            outb        %al, %dx
+
+            xor         %bx, %bx
+            mov         $0x0E, %ah
+            int         $0x10
+
+            pop         %ebp
+            pop         %edx
+            pop         %ebx
+            pop         %eax
+            ret
+
+dump:       push        %eax
+            push        %ebx
+            push        %ecx
+            push        %edx
             push        %esi
             push        %bp
             mov         %sp, %bp
 
-            xor         %bx, %bx
+            xor         %dx, %dx
 
-_prnext:    mov         $COM1+5, %dx
+1:          cmp         %cx, %dx
-            inb         %dx, %al
+            jae         2f
-            test        $0x20, %al
+            inc         %dx
-            jz          _prnext
 
-            lodsb
+            addr32 lodsb
-            or          %al, %al
+            push        %ax
-            jz          _prdone
+            mov         %al, %bl
+            shr         $4, %bx
+            and         $0x0F, %bx
+            mov         hex_digits(%bx), %al
+            call        printch
+            pop         %bx
+            and         $0x0F, %bx
+            mov         hex_digits(%bx), %al
+            call        printch
 
-            mov         $COM1, %dx
+            mov         $' ', %al
-            outb        %al, %dx
+            call        printch
+            test        $0xF, %dx
+            jnz         1b
+            mov         $'\r', %al
+            call        printch
+            mov         $'\n', %al
+            call        printch
+            jmp         1b
 
-            mov         $0x0E, %ah
+2:          mov         $'\r', %al
-            int         $0x10
+            call        printch
-            jmp         _prnext
+            mov         $'\n', %al
+            call        printch
 
-_prdone:    leave
+            leave
             pop         %esi
             pop         %edx
+            pop         %ecx
             pop         %ebx
             pop         %eax
             ret