ovm - ARCHIVED - A stack based virtual machine to act as a target for other programming languages

Age	Commit message (Collapse)	Author
2023-10-31	Introduced new instructions for comparison	Aryadev Chavali
	Comparing signed and unsigned versions of numbers. Same for EQ as well. Notice the irregular pattern of BYTE, CHAR, INT, HWORD,LONG,WORD as OPCODE_IS_TYPE requires the subcodes to be surrounded by BYTE and WORD.
2023-10-31	asm/main logs are now indented and look prettier	Aryadev Chavali

2023-10-31	Lexer now returns errors on failure	Aryadev Chavali
	Currently only for invalid character literals, but still a possible problem.
2023-10-31	parse_word deals with characters now	Aryadev Chavali
	Just takes the character literally as a number.
2023-10-31	Changed asm/parser instruction push-reg->push.reg	Aryadev Chavali

2023-10-29	Make Verbose a universal flag	Aryadev Chavali
	All objects target LIB anyway, so VERBOSE is a universal macro for this code base.
2023-10-29	Added a "usage" message and colours for assembler	Aryadev Chavali
	Prints useful and pretty messages when verbose being at least 1.
2023-10-29	Fixed bug where JUMP_REGISTER couldn't be in bytecode read	Aryadev Chavali

2023-10-29	Fixed bug where reading operand bytecode may stop prematurely	Aryadev Chavali
	This is due to checking for equality instead of just greater than in darr->used against darr->available.
2023-10-29	Added some examples to instruction-test for positive/negative literals	Aryadev Chavali
	Use the push.* instructions to see this.
2023-10-29	Introduced an example source file for all instructions	Aryadev Chavali
	Provides calling conventions, ensures parser and lexer are working correctly. Will be updated as more instructions are introduced and supported in the assembler.
2023-10-29	Auto-fill copyright notice in examples/fib.c	Aryadev Chavali

2023-10-28	Introduce error reporting in asm/main	Aryadev Chavali
	Pretty simple implementation, I've stopped printing the tokens cos I think the lexer is done.
2023-10-28	asm/parser supports all opcodes, introduced parse errors	Aryadev Chavali
	Introduced some functions to parse differing types of opcodes. Use the same style of a.b.c... for namespacing or type specification for certain opcodes. Bit hacky and not tested, but does work. Parse errors can be reported with an exact location using the token column, line.
2023-10-28	Ignore comments (using semicolons) in lexer	Aryadev Chavali
	Easier to do it here than at the parser.
2023-10-28	Introduced a column and line for each token	Aryadev Chavali
	Accurate error reporting can be introduced using this.
2023-10-28	Added macro to do safe subtractions on a word	Aryadev Chavali
	Default C just lets overflows occur for subtraction, so this macro will default to 0 if the subtraction causes an overflow.
2023-10-26	Plugged in asm/parser to asm/main	Aryadev Chavali
	Just prints instructions so far.
2023-10-26	Implemented a rudimentary parser with support for 4 instruction types	Aryadev Chavali

2023-10-26	Added support in lexer for negative numbers	Aryadev Chavali
	Though we deal with unsigned numbers internally, it should be possible to read and manipulate negative numbers through 2s complement. Later on we'll add support for signed operations via 2s complement, so this should be allowed.
2023-10-26	Fixed bug where printing hword of an instruction prints number not hex	Aryadev Chavali
	This is an easy fix.
2023-10-26	asm/main now uses TOKEN_STREAM_AT	Aryadev Chavali

2023-10-26	Lexer forces uppercase for symbols	Aryadev Chavali

2023-10-26	Updated README for targeting VM	Aryadev Chavali

2023-10-26	Makefile now prints dependencies on successful compilation	Aryadev Chavali

2023-10-26	Moved base functions from inst.c to dedicated file	Aryadev Chavali
	Doesn't make sense for them to be in the VM module when they have a more general purpose now.
2023-10-26	vm/main takes a filename as input to execute bytecode	Aryadev Chavali
	Also prints a usage for incorrect usage.
2023-10-26	Auto fill licenses	Aryadev Chavali

2023-10-26	Unified literal for numbers, main program now tokenises	Aryadev Chavali

2023-10-25	Started working on a parser	Aryadev Chavali
	No implementations yet
2023-10-25	Separated lexer from main file in asm	Aryadev Chavali

2023-10-24	Wrote lexer for assembly	Aryadev Chavali
	Pretty simple tokeniser, doesn't do a lot and needs to error check better.
2023-10-24	Removed assertion in darr_read_file	Aryadev Chavali
	If an empty file is read, we want to deal with it in later user code rather than just failing immediately.
2023-10-23	Starting development on assembly language	Aryadev Chavali

2023-10-23	Make root directory an include path, set #include's properly	Aryadev Chavali
	Easier to write includes now just using < with the module name, in comparison to using relative paths.
2023-10-23	Reintroduced example fib.c via examples/ folder	Aryadev Chavali

2023-10-23	Added lib folder for general stuff, introduced as target to Makefile	Aryadev Chavali

2023-10-23	Implemented simple example of a for loop in main	Aryadev Chavali

2023-10-23	src->vm, Makefile is now a bit more abstracted and pretty colours	Aryadev Chavali
	Changed folder names for sake of clarity (will be introducing a new build target soon), and Makefile can now easily support more targets.
2023-10-23	Remove unnecessary log message	Aryadev Chavali

2023-10-23	Added and implemented OP_JUMP_IF_*	Aryadev Chavali
	Performs a jump when the (BYTE\|HWORD\|WORD) at the top of the stack is non zero.
2023-10-23	Extracted code that performs a jump into its own routine	Aryadev Chavali
	Checks if the operand given is a well defined program address, then performs the jump.
2023-10-23	Fixed bug in vm_mov(byte\|hword) where registers aren't set properly	Aryadev Chavali
	This is because we just OR the bits into the specific byte of the word. This means the previous state may leave artefacts as the OR doesn't clear the bits away. To do so, we apply a bit mask to clear the specified byte(s) of the word, then perform the OR.
2023-10-23	Moved macros to extract nth (byte\|hword) from a word to base.h	Aryadev Chavali

2023-10-23	Rearrange what is printed in vm_print_all	Aryadev Chavali
	First the program, then the registers then the stack.
2023-10-23	Check for and handle errors when interpreting bytecode	Aryadev Chavali
	Prints an error message, returns a non zero code based on error code (255 - err). In main, I propagate this exit code.
2023-10-23	Added an example program fib.c	Aryadev Chavali
	This is simply a program with an embedded set of instructions which indefinitely computes and prints fibonacci numbers, computing them in pairs. Does it completely through the virtual machine rather than just hard C instructions. Also amended the Makefile to compile it. Required moving the main.c object file into the dependencies of $(DIST)/$(OUT). I should track the dependencies for fib.c and main.c as well.
2023-10-23	Fixed bugs with ordering of bytes in some operations	Aryadev Chavali
	Also fixed an overflow error in vm_dup_word, where I underflow the index of vm->stack.data which causes a buffer overflow.
2023-10-23	Added and implemented OP_PRINT*	Aryadev Chavali
	Here is where we may have differing interpretations of what the bits in the data pile may actually mean. This in particular refers to printing the signed or unsigned versions of the bits given. Also, interpreting some byte as a character or just a raw number.
2023-10-23	Fixed bug where vm_print_program listing for program was incorrect	Aryadev Chavali
	Only happens when vm_print_program(STDERR), as STDERR occurs before STDOUT on Emacs. So while the lines would print, no instructions would follow. This fixes that by using fp.