Class: Idl::SignCastAst

Inherits:
AstNode show all
Includes:
Rvalue
Defined in:
lib/idlc/ast.rb,
lib/idlc/passes/gen_adoc.rb

Constant Summary

Constants inherited from AstNode

AstNode::Bits1Type, AstNode::Bits32Type, AstNode::Bits64Type, AstNode::BoolType, AstNode::ConstBoolType, AstNode::PossiblyUnknownBits1Type, AstNode::PossiblyUnknownBits32Type, AstNode::PossiblyUnknownBits64Type, AstNode::ReachableFunctionCacheType, AstNode::StringType, AstNode::VoidType

Instance Attribute Summary

Attributes inherited from AstNode

#children, #input, #interval, #parent

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Rvalue

#max_value, #min_value, #truncate, #values

Methods inherited from AstNode

#always_terminates?, #declaration?, #executable?, extract_base_var_name, #find_ancestor, #find_dst_registers, #find_referenced_csrs, #find_src_registers, #freeze_tree, #gen_option_adoc, #input_file, input_from_source_yaml, #inspect, #internal_error, interval_from_source_yaml, #lineno, #lines_around, #nullify_assignments, #pass_find_return_values, #path, #print_ast, #prune, #reachable_exceptions, #reachable_functions, #set_input_file, #set_input_file_unless_already_set, #source_line_file_offsets, #source_starting_offset, #source_yaml, #starting_line, #text_value, #truncation_warn, #type_error, #unindent, value_else, #value_else, value_error, #value_error, value_try, #value_try, write_back_nested

Constructor Details

#initialize(input, interval, exp) ⇒ SignCastAst

Returns a new instance of SignCastAst.



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# File 'lib/idlc/ast.rb', line 4358

def initialize(input, interval, exp) = super(input, interval, [exp])

Class Method Details

.from_h(yaml, source_mapper) ⇒ Object 



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# File 'lib/idlc/ast.rb', line 4395

def self.from_h(yaml, source_mapper)
  raise "Bad YAML" unless yaml.key?("kind") && yaml.fetch("kind") == "sign_cast"

  input = input_from_source_yaml(yaml.fetch("source"), source_mapper)
  interval = interval_from_source_yaml(yaml.fetch("source"))
  SignCastAst.new(
    input, interval,
    T.cast(AstNode.from_h(yaml.fetch("expr"), source_mapper), RvalueAst)
  )
end

Instance Method Details

#const_eval?(symtab) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/idlc/ast.rb', line 4354

def const_eval?(symtab) = true

#expression ⇒ Object 



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# File 'lib/idlc/ast.rb', line 4356

def expression = @children[0]

#gen_adoc(indent = 0, indent_spaces: 2) ⇒ Object 



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# File 'lib/idlc/passes/gen_adoc.rb', line 168

def gen_adoc(indent = 0, indent_spaces: 2)
  "#{' ' * indent}$signed+++(+++#{expression.gen_adoc(0, indent_spaces:)})"
end

#to_h ⇒ Object 



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# File 'lib/idlc/ast.rb', line 4388

def to_h = {
  "kind" => "sign_cast",
  "expr" => expression.to_h,
  "source" => source_yaml
}

#to_idl ⇒ Object 



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# File 'lib/idlc/ast.rb', line 4385

def to_idl = "$signed(#{expression.to_idl})"

#type(symtab) ⇒ Type

Given a specific symbol table, return the type of this node.

Should not be called until #type_check is called with the same arguments

Parameters:

Returns:

  • (Type) —

    The type of the node

Raises:



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# File 'lib/idlc/ast.rb', line 4367

def type(symtab) = expression.type(symtab).clone.make_signed

#type_check(symtab, strict:) ⇒ void

This method returns an undefined value.

type check this node and all children

Calls to #type and/or #value may depend on type_check being called first with the same symtab. If not, those functions may raise an AstNode::InternalError

Parameters:

Raises:



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# File 'lib/idlc/ast.rb', line 4361

def type_check(symtab, strict:)
  expression.type_check(symtab, strict:)
  type_error "$signed cast only works on Bits types" unless expression.type(symtab).kind == :bits
end

#value(symtab) ⇒ Object

Return the compile-time-known value of the node



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# File 'lib/idlc/ast.rb', line 4370

def value(symtab)
  t = expression.type(symtab)
  internal_error "Expecting a bits type" unless t.kind == :bits
  v = expression.value(symtab)

  if ((v >> (t.width - 1)) & 1) == 1
    # twos compliment negate the value
    -(2**t.width - v)
  else
    v
  end
end