589 lines
16 KiB
C
589 lines
16 KiB
C
#include "vm.h"
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#include "device.h"
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#include "opcodes.h"
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#include "str.h"
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/* no inline fn in ANSI C :( */
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#define COMPARE_AND_JUMP(type, op) \
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do { \
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type value, value2; \
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dest = read_u8(vm, code, vm->pc); \
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vm->pc++; \
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src1 = read_u8(vm, code, vm->pc); \
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vm->pc++; \
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src2 = read_u8(vm, code, vm->pc); \
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vm->pc++; \
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value = vm->frames[vm->fp].registers[src1]; \
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value2 = vm->frames[vm->fp].registers[src2]; \
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vm->pc = (value op value2) ? vm->frames[vm->fp].registers[dest] : vm->pc; \
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return true; \
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} while (0)
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#define MATH_OP(type, op) \
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do { \
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dest = read_u8(vm, code, vm->pc); \
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vm->pc++; \
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src1 = read_u8(vm, code, vm->pc); \
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vm->pc++; \
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src2 = read_u8(vm, code, vm->pc); \
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vm->pc++; \
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vm->frames[vm->fp].registers[dest] = (type)vm->frames[vm->fp] \
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.registers[src1] op(type) \
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vm->frames[vm->fp] \
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.registers[src2]; \
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return true; \
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} while (0)
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u32 str_alloc(VM *vm, const char *str, u32 length) {
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u32 str_addr = vm->mp;
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u32 i = 0;
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vm->mp += 4;
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while (i < length) {
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vm->memory[vm->mp++] = str[i++];
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}
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vm->memory[vm->mp++] = '\0';
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write_u32(vm, memory, str_addr, length);
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vm->frames[vm->fp].end = vm->mp;
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return str_addr;
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}
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/**
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* Step to the next opcode in the vm.
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*/
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bool step_vm(VM *vm) {
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u8 opcode, dest, src1, src2;
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u32 v, ptr;
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i32 value;
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/* Get current instruction & Advance to next instruction */
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opcode = vm->code[vm->pc++];
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switch (opcode) {
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case OP_HALT: {
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return false;
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}
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case OP_CALL: {
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u32 jmp = read_u32(vm, code, vm->pc); /* location of function in code */
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vm->pc += 4;
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vm->return_stack[vm->rp++] = vm->pc; /* set return address */
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vm->fp++; /* increment to the next free frame */
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vm->frames[vm->fp].start = vm->mp; /* set start of new memory block */
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vm->pc = jmp;
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return true;
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}
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case OP_RETURN: {
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vm->frames[vm->fp].rp = 0; /* reset register ptr */
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vm->pc = vm->return_stack[--vm->rp]; /* set pc to return address */
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vm->mp =
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vm->frames[vm->fp--].start; /* reset memory pointer to start
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of old slice, pop the frame */
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return true;
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}
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case OP_LOAD_IMM: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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v = read_u32(vm, code, vm->pc);
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vm->pc += 4;
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vm->frames[vm->fp].registers[dest] = v;
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return true;
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}
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case OP_LOAD: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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ptr = read_u32(vm, code, vm->pc);
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vm->pc += 4;
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v = read_u32(vm, memory, ptr);
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vm->frames[vm->fp].registers[dest] = v;
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return true;
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}
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case OP_STORE: {
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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ptr = read_u32(vm, code, vm->pc);
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vm->pc += 4;
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v = vm->frames[vm->fp].registers[src1];
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write_u32(vm, memory, ptr, v);
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return true;
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}
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case OP_PUSH: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->stack[++vm->sp] = vm->frames[vm->fp].registers[dest];
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return true;
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}
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case OP_POP: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] = vm->stack[vm->sp--];
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return true;
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}
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case OP_REG_MOV: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] = vm->frames[vm->fp].registers[src1];
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return true;
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}
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case OP_JMP: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->pc = vm->frames[vm->fp].registers[dest]; /* Jump to address */
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return true;
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}
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case OP_SYSCALL: {
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u32 syscall_id, arg_count;
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u8 first_reg;
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syscall_id = read_u32(vm, code, vm->pc);
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vm->pc += 4;
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arg_count = read_u32(vm, code, vm->pc);
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vm->pc += 4;
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first_reg = read_u8(vm, code, vm->pc);
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vm->pc++;
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switch (syscall_id) {
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case SYSCALL_DEVICE_OPEN: {
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if (arg_count >= 2) {
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Device *dev;
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u32 path_ptr, mode, str_src;
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path_ptr =
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vm->frames[vm->fp].registers[first_reg]; /* R0: path pointer */
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mode = vm->frames[vm->fp].registers[first_reg + 1]; /* R1: mode */
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str_src = path_ptr + 1;
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dev = find_device_by_path(vm, (const char *)&vm->memory[str_src]);
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if (dev) {
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if (dev->ops->open) {
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vm->acc = dev->ops->open(dev->data, mode);
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} else {
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vm->acc = 1; /* success, no open needed */
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}
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} else {
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vm->acc = 0; /* error */
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}
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} else {
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vm->acc = 0; /* error: not enough arguments */
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}
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return true;
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}
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case SYSCALL_DEVICE_READ: {
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if (arg_count >= 3) {
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Device *dev;
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u32 path_ptr, buffer_ptr, size, str_src;
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path_ptr =
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vm->frames[vm->fp].registers[first_reg]; /* R0: path pointer */
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buffer_ptr = vm->frames[vm->fp]
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.registers[first_reg + 1]; /* R1: buffer pointer */
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size = vm->frames[vm->fp].registers[first_reg + 2]; /* R2: size */
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str_src = path_ptr + 1;
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dev = find_device_by_path(vm, (const char *)&vm->memory[str_src]);
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if (dev && dev->ops->read) {
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vm->acc =
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dev->ops->read(dev->data, (u8 *)&vm->memory[buffer_ptr], size);
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} else {
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vm->acc = 0;
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}
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} else {
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vm->acc = 0; /* error: not enough arguments */
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}
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return true;
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}
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case SYSCALL_DEVICE_WRITE: {
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if (arg_count >= 2) {
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Device *dev;
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u32 path_ptr, buffer_ptr, size, str_src;
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path_ptr =
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vm->frames[vm->fp].registers[first_reg]; /* R0: path pointer */
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buffer_ptr = vm->frames[vm->fp]
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.registers[first_reg + 1]; /* R1: buffer pointer */
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size = read_u32(vm, memory, buffer_ptr); /* R2: size */
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str_src = path_ptr += 4;
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dev = find_device_by_path(vm, (const char *)&vm->memory[str_src]);
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if (dev && dev->ops->write) {
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vm->acc = dev->ops->write(dev->data,
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(const u8 *)&vm->memory[buffer_ptr], size);
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} else {
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vm->acc = 0;
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}
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} else {
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vm->acc = 0; /* error: not enough arguments */
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}
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return true;
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}
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case SYSCALL_DEVICE_CLOSE: {
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if (arg_count >= 1) {
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Device *dev;
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u32 path_ptr, str_src;
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path_ptr =
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vm->frames[vm->fp].registers[first_reg]; /* R0: path pointer */
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str_src = path_ptr + 1;
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dev = find_device_by_path(vm, (const char *)&vm->memory[str_src]);
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if (dev && dev->ops->close) {
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i32 result = dev->ops->close(dev->data);
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vm->acc = result;
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} else {
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vm->acc = 0;
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}
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} else {
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vm->acc = 0; /* error: not enough arguments */
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}
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return true;
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}
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case SYSCALL_DEVICE_IOCTL: {
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if (arg_count >= 3) {
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Device *dev;
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u32 path_ptr, args_ptr, cmd, str_src;
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path_ptr =
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vm->frames[vm->fp].registers[first_reg]; /* R0: device path */
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cmd =
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vm->frames[vm->fp].registers[first_reg + 1]; /* R1: ioctl command */
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args_ptr =
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vm->frames[vm->fp].registers[first_reg + 2]; /* R2: args pointer */
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str_src = path_ptr + 1;
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dev = find_device_by_path(vm, (const char *)&vm->memory[str_src]);
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if (dev && dev->ops && dev->ops->ioctl) {
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i32 result = dev->ops->ioctl(dev->data, cmd, &vm->memory[args_ptr]);
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vm->acc = result;
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} else {
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vm->acc = 0; /* error or no ioctl support */
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}
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} else {
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vm->acc = 0; /* error: not enough arguments */
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}
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return true;
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}
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case SYSCALL_EXIT: {
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return false;
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}
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default: {
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vm->acc = 0; /* unknown syscall */
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return true;
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}
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}
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return true;
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}
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case OP_ADD_INT:
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MATH_OP(i32, +);
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case OP_SUB_INT:
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MATH_OP(i32, -);
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case OP_MUL_INT:
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MATH_OP(i32, *);
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case OP_DIV_INT:
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MATH_OP(i32, /);
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case OP_ADD_UINT:
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MATH_OP(u32, +);
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case OP_SUB_UINT:
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MATH_OP(u32, -);
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case OP_MUL_UINT:
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MATH_OP(u32, *);
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case OP_DIV_UINT:
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MATH_OP(u32, /);
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case OP_MUL_REAL: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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src2 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] = (vm->frames[vm->fp].registers[src1] *
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vm->frames[vm->fp].registers[src2]) >>
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16;
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return true;
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}
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case OP_DIV_REAL: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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src2 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] =
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(vm->frames[vm->fp].registers[src1] << 16) /
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vm->frames[vm->fp].registers[src2];
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return true;
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}
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case OP_ADD_REAL: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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src2 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] =
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vm->frames[vm->fp].registers[src1] + vm->frames[vm->fp].registers[src2];
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return true;
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}
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case OP_SUB_REAL: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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src2 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] =
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vm->frames[vm->fp].registers[src1] - vm->frames[vm->fp].registers[src2];
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return true;
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}
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case OP_REAL_TO_INT: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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value = vm->frames[vm->fp].registers[src1];
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if (value >= 0) {
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vm->frames[vm->fp].registers[dest] = value >> 16;
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} else {
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vm->frames[vm->fp].registers[dest] = -((-value) >> 16);
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}
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return true;
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}
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case OP_INT_TO_REAL: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] =
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(vm->frames[vm->fp].registers[src1] << 16);
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return true;
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}
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case OP_REAL_TO_UINT: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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value = vm->frames[vm->fp].registers[src1];
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if (value < 0) {
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vm->frames[vm->fp].registers[dest] = 0;
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} else {
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vm->frames[vm->fp].registers[dest] = AS_UINT(value >> 16);
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}
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return true;
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}
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case OP_UINT_TO_REAL: {
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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vm->frames[vm->fp].registers[dest] =
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AS_INT(vm->frames[vm->fp].registers[src1] << 16);
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return true;
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}
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case OP_JEQ_UINT: {
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COMPARE_AND_JUMP(u32, ==);
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}
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case OP_JGT_UINT: {
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COMPARE_AND_JUMP(u32, >);
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}
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case OP_JLT_UINT: {
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COMPARE_AND_JUMP(u32, <);
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}
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case OP_JLE_UINT: {
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COMPARE_AND_JUMP(u32, <=);
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}
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case OP_JGE_UINT: {
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COMPARE_AND_JUMP(u32, >=);
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}
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case OP_JEQ_INT: {
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COMPARE_AND_JUMP(i32, ==);
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}
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case OP_JGT_INT: {
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COMPARE_AND_JUMP(i32, >);
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}
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case OP_JLT_INT: {
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COMPARE_AND_JUMP(i32, <);
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}
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case OP_JLE_INT: {
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COMPARE_AND_JUMP(i32, <=);
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}
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case OP_JGE_INT: {
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COMPARE_AND_JUMP(i32, >=);
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}
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case OP_JEQ_REAL: {
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COMPARE_AND_JUMP(i32, ==);
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}
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case OP_JGT_REAL: {
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COMPARE_AND_JUMP(i32, >);
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}
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case OP_JLT_REAL: {
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COMPARE_AND_JUMP(i32, <);
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}
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case OP_JGE_REAL: {
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COMPARE_AND_JUMP(i32, >=);
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}
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case OP_JLE_REAL: {
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COMPARE_AND_JUMP(i32, <=);
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}
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case OP_INT_TO_STRING: {
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char buffer[32];
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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int_to_string(AS_INT(vm->frames[vm->fp].registers[src1]), buffer);
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ptr = str_alloc(vm, buffer, strlen(buffer));
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vm->frames[vm->fp].registers[dest] = ptr;
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return true;
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}
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case OP_UINT_TO_STRING: {
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char buffer[32];
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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uint_to_string(vm->frames[vm->fp].registers[src1], buffer);
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ptr = str_alloc(vm, buffer, strlen(buffer));
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vm->frames[vm->fp].registers[dest] = ptr;
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return true;
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}
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case OP_REAL_TO_STRING: {
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char buffer[32];
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dest = read_u8(vm, code, vm->pc);
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vm->pc++;
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src1 = read_u8(vm, code, vm->pc);
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vm->pc++;
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fixed_to_string(AS_INT(vm->frames[vm->fp].registers[src1]), buffer);
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ptr = str_alloc(vm, buffer, strlen(buffer)); /* copy buffer to dest */
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vm->frames[vm->fp].registers[dest] = ptr;
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return true;
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}
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case OP_STRING_TO_INT: {
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/* not implemented yet */
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return false;
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}
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case OP_STRING_TO_UINT: {
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/* not implemented yet */
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return false;
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}
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case OP_STRING_TO_REAL: {
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/* not implemented yet */
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return false;
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}
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}
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return false; /* something bad happened */
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}
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/* Static digit lookup table (0-9) */
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const char digits[10] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
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/* Writes decimal digits of 'value' backwards into 'buf_end' (inclusive),
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stopping at 'buf_start'. Returns pointer to first written digit. */
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char *write_digits_backwards(u32 value, char *buf_end, char *buf_start) {
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char *p = buf_end;
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if (value == 0) {
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|
*--p = '0';
|
|
} else {
|
|
u32 num = value;
|
|
while (num && p > buf_start) {
|
|
*--p = digits[num % 10];
|
|
num /= 10;
|
|
}
|
|
}
|
|
return p;
|
|
}
|
|
|
|
void uint_to_string(u32 value, char *buffer) {
|
|
char temp[16];
|
|
char *start;
|
|
char *end = temp + sizeof(temp) - 1;
|
|
*end = '\0';
|
|
start = write_digits_backwards(value, end, temp);
|
|
strcopy(buffer, start, end - start + 1); /* +1 for null terminator */
|
|
}
|
|
|
|
void int_to_string(i32 value, char *buffer) {
|
|
char temp[17]; /* Extra space for '-' */
|
|
i32 negative = 0;
|
|
u32 abs_value;
|
|
char *end = temp + sizeof(temp) - 1;
|
|
*end = '\0';
|
|
|
|
if (value == (-2147483647 - 1)) { /* INT32_MIN */
|
|
strcopy(buffer, "-2147483648", 12);
|
|
return;
|
|
}
|
|
|
|
if (value == 0) {
|
|
*--end = '0';
|
|
} else {
|
|
if (value < 0) {
|
|
negative = 1;
|
|
abs_value = (u32)(-value);
|
|
} else {
|
|
abs_value = (u32)value;
|
|
}
|
|
|
|
end = write_digits_backwards(abs_value, end, temp);
|
|
|
|
if (negative) {
|
|
*--end = '-';
|
|
}
|
|
}
|
|
|
|
strcopy(buffer, end, temp + sizeof(temp) - end);
|
|
}
|
|
|
|
void fixed_to_string(i32 value, char *buffer) {
|
|
char temp[32];
|
|
i32 negative;
|
|
u32 int_part;
|
|
u32 frac_part, frac_digits;
|
|
char *end = temp + sizeof(temp) - 1;
|
|
*end = '\0';
|
|
|
|
negative = 0;
|
|
if (value < 0) {
|
|
negative = 1;
|
|
value = -value;
|
|
}
|
|
|
|
int_part = AS_UINT(value >> 16);
|
|
frac_part = AS_UINT(value & 0xFFFF);
|
|
|
|
/* Convert fractional part to 5 decimal digits */
|
|
frac_digits = (frac_part * 100000U) / 65536U;
|
|
|
|
/* Trim trailing zeros */
|
|
while (frac_digits > 0 && frac_digits % 10 == 0) {
|
|
frac_digits /= 10;
|
|
}
|
|
|
|
if (frac_digits > 0) {
|
|
end = write_digits_backwards(frac_digits, end, temp);
|
|
*--end = '.';
|
|
}
|
|
|
|
if (int_part == 0 && frac_digits == 0) {
|
|
*--end = '0';
|
|
} else {
|
|
end = write_digits_backwards(int_part, end, temp);
|
|
}
|
|
|
|
if (negative) {
|
|
*--end = '-';
|
|
}
|
|
|
|
strcopy(buffer, end, temp + sizeof(temp) - end);
|
|
}
|