thesis-lisp/vm/vmstate.c

#include "vmstate.h"
#include "vmval.h"
#include "vm.h"

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>

static inline int64_t sximm(uint32_t in) {
    if (in & 0x800000) {
        return in | 0xFFFFFFFFFF000000;
    } else {
        return in;
    }
}

static inline uint64_t encode_ref(struct vm_value *ref) {
    uintptr_t addr = (uintptr_t) ref;
    assert(!(addr & 1));
    if (sizeof(uintptr_t) == 8) {
        return (addr >> 1) | FLAG_REF;
    } else {
        abort();
    }
}

uint64_t pop(struct vm_state *vm) {
    assert(vm->sp != vm->stack_size);
    return vm->stack[vm->sp++];
}

void push(struct vm_state *vm, uint64_t w) {
    assert(vm->sp > 0);
    vm->stack[--vm->sp] = w;
}

void push_ref(struct vm_state *vm, struct vm_value *ref) {
    assert(vm->sp > 0);
    vm->stack[--vm->sp] = encode_ref(ref);
}

void push_integer(struct vm_state *vm, int64_t w) {
    push(vm, w & ~FLAG_REF);
}

uint64_t pop_integer(struct vm_state *vm) {
    uint64_t w = pop(vm);
    assert(!(w & FLAG_REF));
    if (w & (1ULL << 62)) {
        w |= 1ULL << 63;
    }
    return w;
}

void vm_state_init(struct vm_state *vm, size_t stack_size, size_t global_pool_size) {
    vm->stack = calloc(sizeof(uint64_t), stack_size);
    vm->sp = stack_size;
    vm->stack_size = stack_size;

    vm->global_pool = calloc(sizeof(uint64_t), global_pool_size);
    vm->global_pool_size = global_pool_size;

    vector_init(&vm->ref_table, sizeof(struct vm_ref_entry));

    vector_init(&vm->functions, sizeof(struct vm_func_entry));
    vm->fp = 0;
    vm->ip = 0;
}

struct vm_ref_entry *vm_add_ref(struct vm_state *vm) {
    return vector_append(&vm->ref_table);
}

struct vm_func_entry *vm_add_function(struct vm_state *vm) {
    return vector_append(&vm->functions);
}

//static int vm_eval_debug(struct vm_state *vm, uint32_t arg) {
//    uint64_t w0;
//    switch (arg) {
//    case 0x01:
//        w0 = pop(vm);
//        printf("trace: ");
//        vm_print(w0);
//        printf("\n");
//        return 0;
//    default:
//        fprintf(stderr, "Undefined debug argument: 0x%02hhx\n", arg);
//        abort();
//    }
//}

int vm_eval_opcode(struct vm_state *vm, uint32_t opcode) {
    uint64_t w0, w1;
    size_t i0;
    ssize_t ii0;
    struct vm_ref_entry *r0;

    switch (opcode >> 24) {
    case OP_NOT:
        w0 = pop(vm);
        if (null_q(w0)) {
            push_integer(vm, 1);
        } else {
            push_ref(vm, NULL);
        }
        return 0;
//
    case OP_LDNIL:
        push_ref(vm, NULL);
        return 0;
    case OP_LDI:
        push_integer(vm, sximm(opcode & 0xFFFFFF));
        return 0;
    case OP_CAR:
        w0 = pop(vm);
        assert(pair_q(w0));
        push(vm, getref(w0)->v_cons.fat_ar);
        return 0;
    case OP_CDR:
        w0 = pop(vm);
        assert(pair_q(w0));
        push(vm, getref(w0)->v_cons.fat_dr);
        return 0;
    case OP_CONS:
        w0 = pop(vm);
        w1 = pop(vm);
        push_ref(vm, vm_cons(w0, w1));
        return 0;
//
    case OP_LDG:
        i0 = opcode & 0xFFFFFF;
        assert(i0 < vm->global_pool_size);
        push(vm, vm->global_pool[i0]);
        return 0;
    case OP_STG:
        w0 = pop(vm);
        i0 = opcode & 0xFFFFFF;
        assert(i0 < vm->global_pool_size);
        vm->global_pool[i0] = w0;
        return 0;
//
    case OP_TEST:
        w0 = pop(vm);
        if (null_q(w0)) {
            push_integer(vm, 1);
        } else {
            push_ref(vm, NULL);
        }
        return 0;
//
    case OP_XCALL:
        i0 = opcode & 0xFFFFFF;
        r0 = vector_ref(&vm->ref_table, i0);
        assert(r0->flags & REF_NATIVE);
        {
            int (*func) (struct vm_state *) = (void *) r0->address;
            assert(func);
            return func(vm);
        }
    case OP_BF:
        w0 = pop(vm);
        ii0 = sximm(opcode & 0xFFFFFF);
        if (null_q(w0)) {
            assert(ii0 != 0);
            vm->ip += ii0 - 1;
        }
        return 0;
    case OP_JMP:
        ii0 = sximm(opcode & 0xFFFFFF);
        assert(ii0 != 0);
        vm->ip += ii0 - 1;
        return 0;
    case OP_RET:
        return -1;
    default:
        fprintf(stderr, "Undefined opcode: 0x%02hhx\n", opcode >> 24);
        abort();
    }
}

int vm_eval_step(struct vm_state *vm) {
    assert(vm->fp < vm->functions.size);
    struct vm_func_entry *func = vector_ref(&vm->functions, vm->fp);
    uint32_t opcode = func->bytecode[vm->ip++];
    return vm_eval_opcode(vm, opcode);
}