def _array_init_loop(is_primitive):
''' Code that loops through array elements to initialize them.
This code does not save/restore registers, it should only be called from
create_array() '''
# Code that will create the default value for a single array element:
default_value_code = asm_object.create_default_value(is_primitive, False)
loop_start, loop_end = CodeGenManager.get_labels(
'array_init_loop_start', 'array_init_loop_end')
# eax gets set to the an element'ss default value
# ebx stores the length of the array (number of elements)
# ecx is the loop counter
# edx is a pointer to the start of the array
return [
'mov ecx, 0 ; ecx is counter for which array index we\'re at',
'{0}:'.format(loop_start),
'cmp ecx, ebx ; loop condition (check if done all array elements)',
'je {0}'.format(loop_end),
'; init current array elem to default value:',
'push ebx',
default_value_code,
'pop ebx',
'mov [edx + 12 + 4*ecx], eax',
'add ecx, 1 ; increment loop counter',
'jmp {0}'.format(loop_start),
'{0}:'.format(loop_end),
]
def c_gen_code_create_instance(self):
'''Creates an instance of this class in memory and does all prep work so
that the constructor can be called. Precisely, does the following:
1. Allocate memory for the object.
2. Sets a pointer to the CIT on the instance.
3. Initializes all fields to their default value.
The following should be done by the ClassInstanceCreation:
1. Call the parent constructor.
2. Initialize fields declared on the class.
3. Run constructor body.'''
import code_gen.asm.common as common
import code_gen.asm.object as object_
field_init_code = []
for f in self.get_all_fields():
type_node = f.type_node
field_init_code.extend([
'push eax ; save |this|',
object_.create_default_value(type_node.is_primitive,
type_node.is_array),
'mov ebx, eax ; store result in ebx',
'pop eax ; restore |this|',
common.save_instance_field('eax', f, 'ebx'),
])
return [
'global {0}'.format(self.c_create_object_function_label),
'{0}:'.format(self.c_create_object_function_label),
common.malloc(self.c_object_size),
# Class info table
'mov dword [eax], {0}'.format(self.c_cit_label),
field_init_code,
'ret',
]