expressi.inc

一个用纯汇编 写的操作系统 源代码 是用 TASM 编译器写的

      address_sizes_do_not_match:
	cmp	al,0Fh
	jne	invalid_address
	mov	al,bh
	and	al,0Fh
	cmp	al,ah
	jne	invalid_address
      check_ip_relative_address:
	cmp	bh,0F4h
	je	check_dword_value
	cmp	bh,0F8h
	jne	invalid_address
	mov	eax,[edi]
	cdq
	cmp	edx,[edi+4]
	jne	range_exceeded
	ret
      get_address_register:
	or	al,al
	jz	address_register_ok
	cmp	dl,1
	jne	scaled_register
	or	bh,bh
	jnz	scaled_register
	mov	bh,al
      address_register_ok:
	ret
      scaled_register:
	or	bl,bl
	jnz	invalid_address
	mov	bl,al
	mov	cl,dl
	jmp	address_register_ok
      sib_allowed:
	or	bh,bh
	jnz	check_index_scale
	cmp	cl,2
	je	special_index_scale
	cmp	cl,3
	je	special_index_scale
	cmp	cl,5
	je	special_index_scale
	cmp	cl,9
	je	special_index_scale
      check_index_scale:
	or	cl,cl
	jz	address_registers_ok
	cmp	cl,1
	je	address_registers_ok
	cmp	cl,2
	je	address_registers_ok
	cmp	cl,4
	je	address_registers_ok
	cmp	cl,8
	je	address_registers_ok
	jmp	invalid_address
      special_index_scale:
	mov	bh,bl
	dec	cl
      address_registers_ok:
	jmp	check_dword_value
      check_immediate_address:
	cmp	[code_type],64
	jne	check_dword_value
	cmp	[address_size],4
	je	check_dword_value
	jmp	check_qword_value
calculate_relative_offset:
	cmp	[value_undefined],0
	jne	relative_offset_ok
	add	eax,dword [org_origin]
	adc	edx,dword [org_origin+4]
	sub	eax,edi
	sbb	edx,0
	mov	bl,[value_type]
	or	bl,bl
	je	relative_offset_ok
	test	bl,1
	jnz	invalid_use_of_symbol
	cmp	bl,6
	je	plt_relative_offset
	cmp	bl,[labels_type]
	jne	invalid_use_of_symbol
	mov	[value_type],0
	mov	ecx,[symbol_identifier]
	cmp	ecx,[org_symbol]
	je	relative_offset_ok
	mov	[value_type],3
      relative_offset_ok:
	ret
      plt_relative_offset:
	mov	[value_type],7
	ret

preevaluate_logical_expression:
	push	edi
	call	preevaluate_logical_value
      preevaluation_loop:
	cmp	al,0FFh
	je	invalid_logical_expression
	mov	dl,[esi]
	inc	esi
	cmp	dl,'|'
	je	preevaluate_or
	cmp	dl,'&'
	je	preevaluate_and
	cmp	dl,'}'
	je	preevaluation_done
	or	dl,dl
	jnz	invalid_logical_expression
      preevaluation_done:
	pop	edx
	dec	esi
	ret
      preevaluate_or:
	cmp	al,'1'
	je	quick_true
	cmp	al,'0'
	je	leave_only_following
	push	edi
	mov	al,dl
	stos	byte [edi]
	call	preevaluate_logical_value
	pop	ebx
	cmp	al,'0'
	je	leave_only_preceding
	cmp	al,'1'
	jne	preevaluation_loop
	stos	byte [edi]
	xor	al,al
	jmp	preevaluation_loop
      preevaluate_and:
	cmp	al,'0'
	je	quick_false
	cmp	al,'1'
	je	leave_only_following
	push	edi
	mov	al,dl
	stos	byte [edi]
	call	preevaluate_logical_value
	pop	ebx
	cmp	al,'1'
	je	leave_only_preceding
	cmp	al,'0'
	jne	preevaluation_loop
	stos	byte [edi]
	xor	al,al
	jmp	preevaluation_loop
      leave_only_following:
	mov	edi,[esp]
	call	preevaluate_logical_value
	jmp	preevaluation_loop
      leave_only_preceding:
	mov	edi,ebx
	xor	al,al
	jmp	preevaluation_loop
      quick_true:
	call	skip_logical_value
	jc	invalid_logical_expression
	mov	edi,[esp]
	mov	al,'1'
	jmp	preevaluation_loop
      quick_false:
	call	skip_logical_value
	jc	invalid_logical_expression
	mov	edi,[esp]
	mov	al,'0'
	jmp	preevaluation_loop
      invalid_logical_expression:
	pop	edi
	mov	esi,edi
	mov	al,0FFh
	stos	byte [edi]
	ret
skip_logical_value:
	cmp	byte [esi],'~'
	jne	negation_skipped
	inc	esi
	jmp	skip_logical_value
      negation_skipped:
	cmp	byte [esi],'{'
	jne	skip_simple_logical_value
	inc	esi
      skip_logical_expression:
	call	skip_logical_value
	lods	byte [esi]
	or	al,al
	jz	wrongly_structured_logical_expression
	cmp	al,0Fh
	je	wrongly_structured_logical_expression
	cmp	al,'|'
	je	skip_logical_expression
	cmp	al,'&'
	je	skip_logical_expression
	cmp	al,'}'
	je	logical_value_skipped
      wrongly_structured_logical_expression:
	stc
	ret
      skip_simple_logical_value:
	mov	al,[esi]
	or	al,al
	jz	logical_value_skipped
	cmp	al,0Fh
	je	logical_value_skipped
	cmp	al,'}'
	je	logical_value_skipped
	cmp	al,'|'
	je	logical_value_skipped
	cmp	al,'&'
	je	logical_value_skipped
	call	skip_symbol
	jmp	skip_simple_logical_value
      logical_value_skipped:
	clc
	ret

preevaluate_logical_value:
	mov	ebp,edi
      preevaluate_negation:
	cmp	byte [esi],'~'
	jne	preevaluate_negation_ok
	movs	byte [edi],[esi]
	jmp	preevaluate_negation
      preevaluate_negation_ok:
	mov	ebx,esi
	xor	edx,edx
	cmp	byte [esi],'{'
	jne	find_logical_value_boundaries
	movs	byte [edi],[esi]
	push	ebp
	call	preevaluate_logical_expression
	pop	ebp
	cmp	al,0FFh
	je	invalid_logical_value
	cmp	byte [esi],'}'
	jne	invalid_logical_value
	or	al,al
	jnz	preevaluated_expression_value
	movs	byte [edi],[esi]
	ret
      preevaluated_expression_value:
	inc	esi
	lea	edx,[edi-1]
	sub	edx,ebp
	test	edx,1
	jz	expression_negation_ok
	xor	al,1
      expression_negation_ok:
	mov	edi,ebp
	ret
      invalid_logical_value:
	mov	edi,ebp
	mov	al,0FFh
	ret
      find_logical_value_boundaries:
	mov	al,[esi]
	or	al,al
	jz	logical_value_boundaries_found
	cmp	al,'}'
	je	logical_value_boundaries_found
	cmp	al,'|'
	je	logical_value_boundaries_found
	cmp	al,'&'
	je	logical_value_boundaries_found
	or	edx,edx
	jnz	next_symbol_in_logical_value
	cmp	al,0F0h
	je	preevaluable_logical_operator
	cmp	al,0F7h
	je	preevaluable_logical_operator
	cmp	al,0F6h
	jne	next_symbol_in_logical_value
      preevaluable_logical_operator:
	mov	edx,esi
      next_symbol_in_logical_value:
	call	skip_symbol
	jmp	find_logical_value_boundaries
      logical_value_boundaries_found:
	or	edx,edx
	jz	non_preevaluable_logical_value
	mov	al,[edx]
	cmp	al,0F0h
	je	compare_symbols
	cmp	al,0F7h
	je	compare_symbol_types
	cmp	al,0F6h
	je	scan_symbols_list
      non_preevaluable_logical_value:
	mov	ecx,esi
	mov	esi,ebx
	sub	ecx,esi
	jz	invalid_logical_value
	cmp	esi,edi
	je	leave_logical_value_intact
	rep	movs byte [edi],[esi]
	xor	al,al
	ret
      leave_logical_value_intact:
	add	edi,ecx
	add	esi,ecx
	xor	al,al
	ret
      compare_symbols:
	lea	ecx,[esi-1]
	sub	ecx,edx
	mov	eax,edx
	sub	eax,ebx
	cmp	ecx,eax
	jne	preevaluated_false
	push	esi edi
	mov	esi,ebx
	lea	edi,[edx+1]
	repe	cmps byte [esi],[edi]
	pop	edi esi
	je	preevaluated_true
      preevaluated_false:
	mov	eax,edi
	sub	eax,ebp
	test	eax,1
	jnz	store_true
      store_false:
	mov	edi,ebp
	mov	al,'0'
	ret
      preevaluated_true:
	mov	eax,edi
	sub	eax,ebp
	test	eax,1
	jnz	store_false
      store_true:
	mov	edi,ebp
	mov	al,'1'
	ret
      compare_symbol_types:
	push	esi
	lea	esi,[edx+1]
      type_comparison:
	cmp	esi,[esp]
	je	types_compared
	mov	al,[esi]
	cmp	al,[ebx]
	jne	different_type
	cmp	al,'('
	jne	equal_type
	mov	al,[esi+1]
	mov	ah,[ebx+1]
	cmp	al,ah
	je	equal_type
	or	al,al
	jz	different_type
	or	ah,ah
	jz	different_type
	cmp	al,'.'
	je	different_type
	cmp	ah,'.'
	je	different_type
      equal_type:
	call	skip_symbol
	xchg	esi,ebx
	call	skip_symbol
	xchg	esi,ebx
	jmp	type_comparison
      types_compared:
	pop	esi
	cmp	byte [ebx],0F7h
	jne	preevaluated_false
	jmp	preevaluated_true
      different_type:
	pop	esi
	jmp	preevaluated_false
      scan_symbols_list:
	push	edi esi
	lea	esi,[edx+1]
	sub	edx,ebx
	lods	byte [esi]
	cmp	al,'<'
	jne	invalid_symbols_list
      get_next_from_list:
	mov	edi,esi
      get_from_list:
	cmp	byte [esi],','
	je	compare_in_list
	cmp	byte [esi],'>'
	je	compare_in_list
	cmp	esi,[esp]
	jae	invalid_symbols_list
	call	skip_symbol
	jmp	get_from_list
      compare_in_list:
	mov	ecx,esi
	sub	ecx,edi
	cmp	ecx,edx
	jne	not_equal_length_in_list
	mov	esi,ebx
	repe	cmps byte [esi],[edi]
	mov	esi,edi
	jne	not_equal_in_list
      skip_rest_of_list:
	cmp	byte [esi],'>'
	je	check_list_end
	cmp	esi,[esp]
	jae	invalid_symbols_list
	call	skip_symbol
	jmp	skip_rest_of_list
      check_list_end:
	inc	esi
	cmp	esi,[esp]
	jne	invalid_symbols_list
	pop	esi edi
	jmp	preevaluated_true
      not_equal_in_list:
	add	esi,ecx
      not_equal_length_in_list:
	lods	byte [esi]
	cmp	al,','
	je	get_next_from_list
	cmp	esi,[esp]
	jne	invalid_symbols_list
	pop	esi edi
	jmp	preevaluated_false
      invalid_symbols_list:
	pop	esi edi
	jmp	invalid_logical_value

calculate_logical_expression:
	call	get_logical_value
      logical_loop:
	cmp	byte [esi],'|'
	je	logical_or
	cmp	byte [esi],'&'
	je	logical_and
	ret
      logical_or:
	inc	esi
	or	al,al
	jnz	logical_value_already_determined
	push	eax
	call	get_logical_value
	pop	ebx
	or	al,bl
	jmp	logical_loop
      logical_and:
	inc	esi
	or	al,al
	jz	logical_value_already_determined
	push	eax
	call	get_logical_value
	pop	ebx
	and	al,bl
	jmp	logical_loop
      logical_value_already_determined:
	push	eax
	call	skip_logical_value
	jc	invalid_expression
	pop	eax
	jmp	logical_loop
get_logical_value:
	xor	al,al
      check_for_negation:
	cmp	byte [esi],'~'
	jne	negation_ok
	inc	esi
	xor	al,-1
	jmp	check_for_negation
      negation_ok:
	push	eax
	mov	al,[esi]
	cmp	al,'{'
	je	logical_expression
	cmp	al,0FFh
	je	invalid_expression
	cmp	al,88h
	je	check_for_defined
	cmp	al,89h
	je	check_for_used
	cmp	al,'0'
	je	given_false
	cmp	al,'1'
	je	given_true
	call	get_value
	mov	bl,[value_type]
	push	eax edx ebx
	mov	al,[esi]
	or	al,al
	jz	logical_number
	cmp	al,0Fh
	je	logical_number
	cmp	al,'}'
	je	logical_number
	cmp	al,'&'
	je	logical_number
	cmp	al,'|'
	je	logical_number
	inc	esi
	mov	[compare_type],al
	call	get_value
	pop	ebx
	cmp	[next_pass_needed],0
	jne	values_ok
	cmp	bl,[value_type]
	jne	invalid_use_of_symbol
      values_ok:
	pop	ecx ebx
	cmp	[compare_type],'='
	je	check_equal
	cmp	[compare_type],'>'
	je	check_greater
	cmp	[compare_type],'<'
	je	check_less
	cmp	[compare_type],0F1h
	je	check_not_equal
	cmp	[compare_type],0F2h
	je	check_not_less
	cmp	[compare_type],0F3h
	je	check_not_greater
	jmp	invalid_expression
      check_equal:
	cmp	eax,ebx
	jne	return_false
	cmp	edx,ecx
	jne	return_false
	jmp	return_true
      check_greater:
	cmp	edx,ecx
	jl	return_true
	jg	return_false
	cmp	eax,ebx
	jb	return_true
	jae	return_false
      check_less:
	cmp	edx,ecx
	jl	return_false
	jg	return_true
	cmp	eax,ebx
	jbe	return_false
	ja	return_true
      check_not_less:
	cmp	edx,ecx
	jl	return_true
	jg	return_false
	cmp	eax,ebx
	jbe	return_true
	ja	return_false
      check_not_greater:
	cmp	edx,ecx
	jl	return_false
	jg	return_true
	cmp	eax,ebx
	jb	return_false
	jae	return_true
      check_not_equal:
	cmp	eax,ebx
	jne	return_true
	cmp	edx,ecx
	jne	return_true
	jmp	return_false
      logical_number:
	pop	ebx edx eax
	or	bl,bl
	jnz	invalid_expression
	or	eax,edx
	jnz	return_true
	jmp	return_false
      check_for_defined:
	or	bl,-1
	lods	word [esi]
	cmp	ah,'('
	jne	invalid_expression
      check_expression:
	lods	byte [esi]
	or	al,al
	jz	defined_string
	cmp	al,'.'
	je	defined_fp_value
	cmp	al,')'
	je	expression_checked
	cmp	al,'!'
	je	invalid_expression
	cmp	al,0Fh
	je	check_expression
	cmp	al,10h
	je	defined_register
	cmp	al,11h
	je	check_if_symbol_defined
	cmp	al,80h
	jae	check_expression
	movzx	eax,al
	add	esi,eax
	jmp	check_expression
      defined_register:
	inc	esi
	jmp	check_expression
      defined_fp_value:
	add	esi,12
	jmp	expression_checked
      defined_string:
	lods	dword [esi]
	add	esi,eax
	inc	esi
	jmp	expression_checked
      check_if_symbol_defined:
	lods	dword [esi]
	cmp	eax,-1
	je	invalid_expression
	cmp	eax,0Fh
	jb	check_expression
	je	reserved_word_used_as_symbol
	test	byte [eax+8],4
	jnz	no_prediction
	test	byte [eax+8],1
	jz	symbol_predicted_undefined
	mov	cx,[current_pass]
	sub	cx,[eax+16]
	jz	check_expression
	cmp	cx,1
	ja	symbol_predicted_undefined
	or	byte [eax+8],40h+80h
	jmp	check_expression
      no_prediction:
	test	byte [eax+8],1
	jz	symbol_undefined
	mov	cx,[current_pass]
	sub	cx,[eax+16]
	jz	check_expression
	jmp	symbol_undefined
      symbol_predicted_undefined:
	or	byte [eax+8],40h
	and	byte [eax+8],not 80h
      symbol_undefined:
	xor	bl,bl
	jmp	check_expression
      expression_checked:
	mov	al,bl
	jmp	logical_value_ok
      check_for_used:
	lods	word [esi]
	cmp	ah,2
	jne	invalid_expression
	lods	dword [esi]
	cmp	eax,0Fh
	jb	invalid_use_of_symbol
	je	reserved_word_used_as_symbol
	inc	esi
	test	byte [eax+8],8
	jz	not_used
	mov	cx,[current_pass]
	sub	cx,[eax+18]
	jz	return_true
	cmp	cx,1
	ja	not_used
	or	byte [eax+8],10h+20h
	jmp	return_true
      not_used:
	or	byte [eax+8],10h
	and	byte [eax+8],not 20h
	jmp	return_false
      given_false:
	inc	esi
      return_false:
	xor	al,al
	jmp	logical_value_ok
      given_true:
	inc	esi
      return_true:
	or	al,-1
	jmp	logical_value_ok
      logical_expression:
	inc	esi
	call	calculate_logical_expression
	push	eax
	lods	byte [esi]
	cmp	al,'}'
	jne	invalid_expression
	pop	eax
      logical_value_ok:
	pop	ebx
	xor	al,bl
	ret