Compiling four, p code instructions
Because the system is simpler, the underlying hardware is simplified:
1, there is no register, only one data stack
2, only the main memory for storage, access operations
3, only support main memory indirect addressing
4, you can find symbols in the table symbol, return the symbolic address
Instruction sheet (not completed)
Mnemonics
Format
Description
Push
Push <address>
Pushes <address> points to content
Pop
Pop <address>
To bounce the top of the stack into <address> point position
jmp
JMP <address>
Unconditional jump to <address> point to code
Jt
JT <address> <goal>
Jump to <goal> point to code if <address> point to is true
V. Error information table
(defined in the Compiler.exception.ErrorMessage interface)
Analyzing_failure
File cannot be parsed
class_defined
Repeating class definition
class_not_defined
Class is not defined
identifier_defined
Duplicate identifier definition
identifier_not_defined
Identifier Not defined
Illegal_expression
An illegal expression
Illegal_grammer
Syntax error
Illegal_operation
Illegal operation
Illegal_token
Identifier cannot parse
method_defined
Duplicate method definition
not_allocated
Memory Not allocated
Out_of_memory
Memory is full
Read_file
File cannot be read
Type_unmatched
Type mismatch
