CHANGELOG.md

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

Unreleased

Nothing yet!

[1.0.7] - 2021-03-28

Fixed

• Custom OPCODE instructions (i.e., those not encoding valid HERA instructions) can now be assembled.

[1.0.6] - 2021-01-13

Fixed

• The assembler produces correct offsets for branches in the presence of debugging operations.

[1.0.5] - 2020-12-??

Fixed

• The assembler no longer produces code for debugging instructions like print_reg.
• ASR now rounds towards negative infinity for negative numbers instead of zero.
• DEC and SUB now set the carry flag correctly in certain edge cases.

[1.0.4] - 2020-11-02

Added

• The command output includes the current version of the HERA language.

[1.0.3] - 2020-10-28

Added

• Start-up message for debugger with instructions for new users.
• Entering a blank line in the debugger repeats the previous command, like in gdb.

[1.0.2] - 2019-10-17

Fixed

• Runtime errors on Python 3.7 due to use of typing library.

[1.0.0] - 2019-08-28

Added

• The doc debugging command, for viewing documentation on individual HERA operations.
• The parser now understands C-style #ifdef and #ifndef macros, with HERA_PY as the only defined symbol.
• The register calling convention version of the Tiger standard library function chr
• The --init command-line option for initializing registers.
• New --throttle=<n> syntax for the --throttle option.

Fixed

• The register calling convention version of the Tiger standard library function getchar, previously broken, has been fixed.

[0.8.1] - 2019-03-09

Added

• The OPCODE instruction.
• The asm and dis debugging commands, for assembling and disassembling HERA code in the debugger.

Changed

• The readline library is no longer required for hera to run.

[0.8.0] - 2019-03-07

Added

• The disassembler subcommand.
• The --throttle flag, to limit the number of operations executed on a single run.
• The --credits flag.

Fixed

• Newlines are no longer semi-randomly printed to standard error in preprocessing and assembling mode.

[0.7.0] - 2019-02-13

Added

• The assemble subcommand, for assembling HERA programs into raw machine code.
• The clear debugging command, for clearing breakpoints.
• The break debugging command now accepts a special argument . which sets a breakpoint at the current line.
• The break debugging command now accepts arguments of the form <path>:<line> for setting breakpoints in different files.

Changed

• The break debugging command now prints the location of the breakpoint that it set.
• The preprocess subcommand now prints its normal output to standard out instead of standard error.

Fixed

• When no file path is provided, the break debugging command defaults to the current file (whereas behavior was unpredictable before).
• assign commands in the debugger can now be undone.
• In the debugging minilanguage, the subtraction operator no longer needs to be separated from integer literals by whitespace.

[0.6.0] - 2019-02-10

Added

• Hexadecimal and octal escape sequences are now accepted in character and string literals.
• Support for parameters-in-registers version of the Tiger standard library.

Changed

• Execution times of long-running programs has been cut down by roughly 50%.
• Use of SWI and RTI operations now result in parse-time errors instead of run-time warnings.
• HERA files may no longer contain non-ASCII bytes.
• Type errors are detected even in files with parse errors.
• The --no-debug flag has been renamed to --no-debug-ops.
• The jump debugging command has been renamed to goto.
• When __eval results in a Python exception, the error message with the location is printed to standard error, rather than the raw Python traceback.

Removed

• The jump debugging command (now called goto) may no longer be invoked with no arguments.

Fixed

• The debugger no longer crashes when printing the value of a label on the last line of a program.
• The debugger no longer crashes when list or ll is invoked after the end of the program.
• A relative branch to a label whose instruction number is greater than 255 is no longer erroneously reported as an error.

[0.5.2] - 2019-02-02

Added

• The warn-octal-off flag.
• The info command now accepts one or more argument for specific aspects of the program state.
• The info command can now print information about the program's call stack.
• The help command now accepts abbreviated command names.

Changed

• The --no-ret-warn flag has been renamed to --warn-return-off.
• The --big-stack and --warn-return-off flags can no longer be used with the preprocess subcommand.

Fixed

• hera-py now installs with Python 3.4 without errors. I believe this was broken in version 0.5.1.
• The debugger now executes data statements on start-up.
• The execute debugging command now prints an error message when invoked with no arguments.

[0.5.1] - 2019-01-31

Added

• Arithmetic operations are supported in printing and assigning values in the debugger.
• Much more informative messages for parse errors.
• Detection of invalid return addresses, and accompanying --no-ret-warn flag.
• The undo debugging command.
• The on and off debugging commands for flag manipulation.
• The next debugging command now takes an optional argument.
• The print debugging command now takes accepts an optional format specifier argument.
• The print debugging command now takes multiple comma-separated arguments.
• Printing the program counter or PC_ret (R13) in the debugger now indicates what line of code the registers correspond to.
• The --no-debug command-line flag.

Changed

• The restart debugging command may no longer be abbreviated.
• The skip debugging command has been renamed to jump.
• Debugger now prints three lines of context instead of one after commands that affect the program counter.
• The syntax for memory locations in the debugger minilanguage is now @<address> instead of M[address].

Removed

• The +n argument to the jump debugging command.
• Flags can no longer be printed with the print debugging command. Use the info command instead.
• Flags can no longer be changed with the assign debugging command. Use the new on and off commands instead.

Fixed

• A label may no longer be the second argument to RETURN.
• The assign debugging command no longer prints a spurious error message when invoked.
• Negative numbers are parsed correctly in the debugging minilanguage.
• The debugger now respects the --no-color command-line flag.
• The printed register values after program execution now correctly print negative numbers under the signed interpretation of 16 bits.
• The step command no longer stops prematurely when the number of instructions executed exceeds the length of the program.
• Printing invalid registers in the debugger no longer crashes it.

[0.5.0] - 2019-01-27

Added

• Error messages for #include with non-existent file now print the line number.
• The list and ll debugging commands.
• The execute debugging command.
• The info debugging command.
• The assign debugging command, and its alias x = y.
• The step debugging command.
• The debugging expresson mini-language.
• A warning is printed when R11 is used as the second argument of NOT.
• A warning is printed when CALL and RETURN are used with atypical registers.
• help debugging command takes one or more arguments and prints more detailed help messages for specific commands.
• TIGER_STRING is accepted as an alias for LP_STRING.
• --big-stack command-line flag.

Changed

• Relative branch instructions can now target labels.
• Warning for zero-prefixed octal literals will only be printed once per program, rather than for every occurrence.
• Data statements may never follow code, even when in different files.
• ANSI colors are not used when standard error is not a tty-like device.
• Invalid backslash escapes in string literals are now errors.
• Newlines in string literals are no longer allowed.

Fixed

• Use of undefined labels gives proper error message instead of Python exception.
• continue in debugger doesn't get stuck on breakpoints.
• break debugging command now accepts labels as arguments.
• Constants and data labels cannot be used as branch targets.
• Re-defined constants prevent execution, instead of just printing an error message.
• Passing too few parameters to SET no longer crashes the program.
• Constants can no longer be used before they are declared.
• Invalid zero-prefixed octal literals no longer crash the interpreter.
• Labels are calculated correctly after branches on registers.
• skip debugging command no longer executes instructions, matching its help description.
• Symbols beginning with "m" can now be printed in the debugger.
• Too few arguments to CALL op now causes an error message to be printed, instead of crashing the interpreter.
• Invalid backslash escapes in character literals now cause an error instead of crashing the interpreter.

Removed

• The --lines command-line argument.

[0.4.0] - 2019-01-02

Added

• Interactive debugging!
• Support for PC_ret and FP_alt named registers.
• Support for #include directive.
• Runtime errors for use of SWI and RTI instructions now show line of code, and are only emitted once per program run.

Fixed

• DSKIP with a named constant argument works correctly.
• Symbols (labels, constants and data labels) cannot be redefined.

[0.3.0] - 2018-12-14

Added

• Static type-checking.
• --verbose and --quiet flags.
• Zero-prefixed octal numbers (with a warning), for backwards compatibility with HERA-C.
• Limited support for the SWI and RTI operations.
• Character literals can be used in HERA code.

Changed

• Order of flags in debugging output, to match HERA-C.
• Static data begins at memory address 0xc000, per the HERA manual.

Fixed

• Label names can begin with a valid register (e.g., R1_INIT).
• Data statements no longer cause labels to resolve to the incorrect line number.

Removed

• --no-dump-state flag (use --quiet instead).

[0.2.0] - 2018-11-14

Added

• Data statements: CONSTANT, DLABEL, INTEGER, LP_STRING, and DSKIP.
• SP as an alias for R15.

Changed

• The assembly subcommand has been renamed to preprocess.

[0.1.1] - 2018-11-09

Added

• Support for Python 3.4 and 3.5.

[0.1.0] - 2018-11-09

Initial release with support for all HERA instructions and pseudo-instructions, excluding data statements.