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  1. section .data
  2. 	rmodemsg db 10,'Processor is in Real Mode'
  3. 	rmsg_len:equ $-rmodemsg
  4.  
  5. 	pmodemsg db 10,'Processor is in Protected Mode'
  6. 	pmsg_len:equ $-pmodemsg
  7.  
  8. 	gdtmsg db 10,'GDT Contents are::'
  9. 	gmsg_len:equ $-gdtmsg
  10.  
  11. 	ldtmsg db 10,'LDT Contents are::'
  12. 	lmsg_len:equ $-ldtmsg
  13.  
  14. 	idtmsg db 10,'IDT Contents are::'
  15. 	imsg_len:equ $-idtmsg
  16.  
  17. 	trmsg db 10,'Task Register Contents are::'
  18. 	tmsg_len: equ $-trmsg
  19.  
  20. 	mswmsg db 10,'Machine Status Word::'
  21. 	mmsg_len:equ $-mswmsg
  22.  
  23. 	colmsg db ':'
  24.  
  25. 	nwline db 10
  26. ;-------------------------.bss section------------------------------
  27. section .bss
  28. 	gdt resd 1
  29. 	    resw 1
  30. 	ldt resw 1
  31. 	idt resd 1
  32. 	    resw 1
  33. 	tr  resw 1
  34.  
  35. 	cr0_data resd 1
  36.  
  37. 	dnum_buff resb 04
  38.  
  39. %macro print 2
  40. 	mov rax,01
  41. 	mov rdi,01
  42. 	mov rsi,%1
  43. 	mov rdx,%2
  44. 	syscall
  45. %endmacro
  46.  
  47. ;------------------------.text section -----------------------------
  48. section .text
  49. global _start
  50. _start:	
  51. 	smsw eax		;Reading CR0. As MSW is 32-bit cannot use RAX register. 
  52.  
  53. 	mov [cr0_data],rax
  54.  
  55. 	bt rax,1		;Checking PE bit, if 1=Protected Mode, else Real Mode
  56. 	jc prmode
  57. 	print rmodemsg,rmsg_len
  58. 	jmp nxt1
  59.  
  60. prmode:	print pmodemsg,pmsg_len
  61.  
  62. nxt1:	sgdt [gdt]
  63. 	sldt [ldt]
  64. 	sidt [idt]
  65. 	str [tr]
  66. 	print gdtmsg,gmsg_len
  67.  
  68. 	mov bx,[gdt+4]
  69. 	call print_num
  70.  
  71. 	mov bx,[gdt+2]
  72. 	call print_num
  73.  
  74. 	print colmsg,1
  75.  
  76. 	mov bx,[gdt]
  77. 	call print_num
  78.  
  79. 	print ldtmsg,lmsg_len
  80. 	mov bx,[ldt]
  81. 	call print_num
  82.  
  83. 	print idtmsg,imsg_len
  84.  
  85. 	mov bx,[idt+4]
  86. 	call print_num
  87.  
  88. 	mov bx,[idt+2]
  89. 	call print_num
  90.  
  91. 	print colmsg,1
  92.  
  93. 	mov bx,[idt]
  94. 	call print_num
  95.  
  96. 	print trmsg,tmsg_len
  97.  
  98. 	mov bx,[tr]
  99. 	call print_num
  100.  
  101. 	print mswmsg,mmsg_len
  102.  
  103. 	mov bx,[cr0_data+2]
  104. 	call print_num
  105.  
  106. 	mov bx,[cr0_data]
  107. 	call print_num
  108.  
  109. 	print nwline,1
  110.  
  111.  
  112. exit:	mov rax,60
  113. 	xor rdi,rdi
  114. 	syscall
  115.  
  116. print_num:
  117. 	mov rsi,dnum_buff	;point esi to buffer
  118.  
  119. 	mov rcx,04		;load number of digits to printlay 
  120.  
  121. up1:
  122. 	rol bx,4		;rotate number left by four bits
  123. 	mov dl,bl		;move lower byte in dl
  124. 	and dl,0fh		;mask upper digit of byte in dl
  125. 	add dl,30h		;add 30h to calculate ASCII code
  126. 	cmp dl,39h		;compare with 39h
  127. 	jbe skip1		;if less than 39h skip adding 07 more 
  128. 	add dl,07h		;else add 07
  129. skip1:
  130. 	mov [rsi],dl	;store ASCII code in buffer
  131. 	inc rsi			;point to next byte
  132. 	loop up1		;decrement the count of digits to printlay
  133. 				    ;if not zero jump to repeat
  134.  
  135. 	print dnum_buff,4	;printlay the number from buffer
  136.  
  137. 	ret
Success #stdin #stdout 0.01s 5288KB
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stdin
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Standard input is empty
stdout
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Processor is in Protected Mode
GDT Contents are::0003C000:007F
LDT Contents are::0000
IDT Contents are::00000000:0FFF
Task Register Contents are::0040
Machine Status Word::8005FFFF
https://ideone.com/b3BiAB
language:
Assembler 64bit (nasm 2.14)
created:
1 day ago
visibility:
public

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