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2023-10-23Fixed bug where vm_print_program listing for program was incorrectAryadev 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.
2023-10-22Coupled some routines together, implemented OP_PLUS_*, -vm_peekAryadev Chavali
Routines that use the stack for their operands i.e. aren't supplied operands directly all have the same signature. We may as well stick them all together in one array and one conditional, just reduces the number of branches. Also looks nicer. Implemented OP_PLUS_*. Pretty simple to implement. Deleted vm_peek as it was only necessary to update the `ret` register.
2023-10-22Added runtime errors to virtual machineAryadev Chavali
Every vm routine now returns an err_t, which is an enumeration of possible error states. ERR_OK represents the good state and is 0 so error checking seems very natural in terms of language `if (err) ...`. Errors bubble up the runtime, with any callers forced to check if an error occurred. This does mean that routines that call other routines cannot provide an accurate trace of the subcaller (based on the fact that an error is generated for the current instruction), but this should be a non issue as no instruction should be complex enough to need proper traces.
2023-10-22Added and implemented OP_JUMP_(STACK|REGISTER)Aryadev Chavali
Uses the stack and register, respectively, to jump to an absolute address. The stack based jump pops a word off the stack to perform a jump, while the register based one uses the operand to figure out which register to use.
2023-10-22Removed `ret` registerAryadev Chavali
Wasn't useful or necessary.
2023-10-22Added and implemented OP_JUMP_ABSAryadev Chavali
Jumps to the operand given, interpreted as a word, an absolute address.
2023-10-22Fixed bug in vm_execute_all, if no OP_HALT then program kept goingAryadev Chavali
This adds a bound on vm_execute_all to stop program->ptr from going past program->max.
2023-10-22Implemented vm_* routines for OP_DUP and vm_execute codeAryadev Chavali
2023-10-22Use conversion functions for (h)word to and from bytes instead of bit shiftingAryadev Chavali
Wasn't very secure for endianness, and using these helpers abstracts the details away a bit in case I want to enforce a certain system.
2023-10-22Added NUMBER_OF_OPCODES which aids in compilation errorsAryadev Chavali
If I add a new operand I want the build system to be more helpful in finding the places I need to change to make it work.
2023-10-22Fix bug where accessing byte/hword registers > 8 wouldn't workAryadev Chavali
This is because we were checking them as if they were word registers.
2023-10-22When VEROBSE flag is set greater than 0, print traces in vm_execute_allAryadev Chavali
For each cycle, print the cycle and any changes. We track changes on the stack by remembering the previous stack pointer. For registers, I remember the previous array of registers and do a byte level compare of the current registers and the remembered ones. Produces pretty log messages and an easy way to track execution.
2023-10-22Changed formats for vm_print_(stack|program)Aryadev Chavali
Easier to read now
2023-10-22Store the result of OP_POP in the last register as a wordAryadev Chavali
Instead of making routines to handle data in the `ret` register, just store the result of POP into the last word register. This means we are no longer using vm_pop_* or POP_ROUTINES for the vm_execute script on OP_POP: instead we'll just use vm_mov_* which automatically pops the datum for us, while moving the datum to the last register.
2023-10-21Implemented vm routines for OP_EQ_*Aryadev Chavali
2023-10-21Implemented vm routines for OP_XOR_*Aryadev Chavali
2023-10-21Implemented vm routines for OP_AND_*Aryadev Chavali
2023-10-21Implemented vm routines for OP_OR_*Aryadev Chavali
2023-10-21Implemented vm routines for OP_NOT_*Aryadev Chavali
2023-10-21Added vm_execute_all which executes an entire programAryadev Chavali
Handles OP_HALT
2023-10-21Switched from floats to halfwordAryadev Chavali
Registers are now just words, with pushing from and moving to registers with specified subtypes just pushing those types into the word registers. That means there are 8 word registers which can act as 16 half word registers, which themselves can act as 64 byte registers.
2023-10-16Implemented vm_print_* routinesAryadev Chavali
Prints each aspect of the vm, and vm_print_all does it all.
2023-10-16MOV now uses the stack, removed register member in inst_tAryadev Chavali
Instead of taking an operand and a register, mov just uses the stack for the operand. Therefore, there's no need for a register member in inst_t. As a result, PUSH_*_REGISTER now uses the operand for the register.
2023-10-15Better checking of opcode typesAryadev Chavali
Introduced an enum (opcode_type_t) for the masks and values of each opcode, which allows defining a single enum which checks an opcode by a opcode_type_t.
2023-10-15Moved vm_* code to its own file (runtime.(h|c))Aryadev Chavali