+/*
+ * EmbedVM - Embedded Virtual Machine for uC Applications
+ *
+ * Copyright (C) 2011 Clifford Wolf <clifford@clifford.at>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "embedvm.h"
+
+static inline int16_t signext(uint16_t val, uint16_t mask)
+{
+ val = val & mask;
+ if ((val & ~(mask >> 1)) != 0)
+ val |= ~mask;
+ return val;
+}
+
+extern void embedvm_exec(struct embedvm_s *vm)
+{
+ uint8_t opcode = vm->mem_read(vm->ip, false, vm->user_ctx);
+ uint16_t addr = 0;
+ int16_t a = 0, b = 0;
+ int8_t sfa = 0;
+
+ switch (opcode)
+ {
+ case 0x00 ... 0x3f:
+ sfa = signext(opcode, 0x3f);
+ embedvm_push(vm, embedvm_local_read(vm, sfa));
+ vm->ip++;
+ break;
+ case 0x40 ... 0x7f:
+ sfa = signext(opcode, 0x3f);
+ embedvm_local_write(vm, sfa, embedvm_pop(vm));
+ vm->ip++;
+ break;
+ case 0x80+0 ... 0x80+11:
+ case 0xa8+0 ... 0xa8+5:
+ b = embedvm_pop(vm);
+ case 0x80+12 ... 0x80+14:
+ a = embedvm_pop(vm);
+ switch (opcode)
+ {
+ case 0x80 + 0: embedvm_push(vm, a + b); break;
+ case 0x80 + 1: embedvm_push(vm, a - b); break;
+ case 0x80 + 2: embedvm_push(vm, a * b); break;
+ case 0x80 + 3: embedvm_push(vm, a / b); break;
+ case 0x80 + 4: embedvm_push(vm, a % b); break;
+ case 0x80 + 5: embedvm_push(vm, a << b); break;
+ case 0x80 + 6: embedvm_push(vm, a >> b); break;
+ case 0x80 + 7: embedvm_push(vm, a & b); break;
+ case 0x80 + 8: embedvm_push(vm, a | b); break;
+ case 0x80 + 9: embedvm_push(vm, a ^ b); break;
+ case 0x80 + 10: embedvm_push(vm, a && b); break;
+ case 0x80 + 11: embedvm_push(vm, a || b); break;
+ case 0x80 + 12: embedvm_push(vm, ~a); break;
+ case 0x80 + 13: embedvm_push(vm, -a); break;
+ case 0x80 + 14: embedvm_push(vm, !a); break;
+ case 0xa8 + 0: embedvm_push(vm, a < b); break;
+ case 0xa8 + 1: embedvm_push(vm, a <= b); break;
+ case 0xa8 + 2: embedvm_push(vm, a == b); break;
+ case 0xa8 + 3: embedvm_push(vm, a != b); break;
+ case 0xa8 + 4: embedvm_push(vm, a >= b); break;
+ case 0xa8 + 5: embedvm_push(vm, a > b); break;
+
+ }
+ vm->ip++;
+ break;
+ case 0x90 ... 0x97:
+ a = signext(opcode, 0x07);
+ if ((a & 0x04) != 0)
+ a |= ~0x07;
+ embedvm_push(vm, a);
+ vm->ip++;
+ break;
+ case 0x98:
+ a = vm->mem_read(vm->ip+1, false, vm->user_ctx) & 0x00ff;
+ embedvm_push(vm, a);
+ vm->ip += 2;
+ break;
+ case 0x99:
+ a = vm->mem_read(vm->ip+1, false, vm->user_ctx) & 0x00ff;
+ embedvm_push(vm, signext(a, 0x00ff));
+ vm->ip += 2;
+ break;
+ case 0x9a:
+ a = vm->mem_read(vm->ip+1, true, vm->user_ctx);
+ embedvm_push(vm, a);
+ vm->ip += 3;
+ break;
+ case 0x9b:
+ a = embedvm_pop(vm);
+ if (0) {
+ case 0x9c:
+ a = 0;
+ }
+ vm->sp = vm->sfp;
+ vm->ip = embedvm_pop(vm);
+ vm->sfp = embedvm_pop(vm);
+ if ((vm->sfp & 1) != 0)
+ vm->sfp &= ~1;
+ else
+ embedvm_push(vm, a);
+ break;
+ case 0x9d:
+ embedvm_pop(vm);
+ vm->ip++;
+ break;
+ case 0x9e:
+ addr = embedvm_pop(vm);
+ if (vm->mem_read(vm->ip+1, false, vm->user_ctx) == 0x9d) {
+ embedvm_push(vm, vm->sfp | 1);
+ embedvm_push(vm, vm->ip + 2);
+ } else {
+ embedvm_push(vm, vm->sfp);
+ embedvm_push(vm, vm->ip + 1);
+ }
+ vm->sfp = vm->sp;
+ vm->ip = addr;
+ break;
+ case 0x9f:
+ vm->ip = embedvm_pop(vm);
+ break;
+ case 0xa0 ... 0xa0+7:
+ if ((opcode & 1) == 0) {
+ addr = vm->ip + signext(vm->mem_read(vm->ip+1, false, vm->user_ctx), 0x00ff);
+ vm->ip += 2;
+ } else {
+ addr = vm->ip + vm->mem_read(vm->ip+1, true, vm->user_ctx);
+ vm->ip += 3;
+ }
+ switch (opcode)
+ {
+ case 0xa0:
+ case 0xa1:
+ vm->ip = addr;
+ break;
+ case 0xa2:
+ case 0xa3:
+ if (vm->mem_read(vm->ip, false, vm->user_ctx) == 0x9d) {
+ embedvm_push(vm, vm->sfp | 1);
+ embedvm_push(vm, vm->ip + 1);
+ } else {
+ embedvm_push(vm, vm->sfp);
+ embedvm_push(vm, vm->ip);
+ }
+ vm->sfp = vm->sp;
+ vm->ip = addr;
+ break;
+ case 0xa4:
+ case 0xa5:
+ if (embedvm_pop(vm))
+ vm->ip = addr;
+ break;
+ case 0xa6:
+ case 0xa7:
+ if (!embedvm_pop(vm))
+ vm->ip = addr;
+ break;
+ }
+ break;
+ case 0xae:
+ embedvm_push(vm, vm->sp);
+ vm->ip++;
+ break;
+ case 0xaf:
+ embedvm_push(vm, vm->sfp);
+ vm->ip++;
+ break;
+ case 0xb0 ... 0xb0+15:
+ {
+ uint8_t argc = embedvm_pop(vm);
+ int16_t argv[argc];
+ for (sfa=0; sfa<argc; sfa++)
+ argv[sfa] = embedvm_pop(vm);
+ a = vm->call_user(opcode - 0xb0, argc, argv, vm->user_ctx);
+ embedvm_push(vm, a);
+ }
+ vm->ip++;
+ break;
+ case 0xc0 ... 0xef:
+ if ((opcode & 0x07) == 5) {
+ /* this is a "bury" instruction */
+ uint8_t depth = (opcode >> 3) & 0x07;
+ int16_t stack[depth+1];
+ for (sfa = 0; sfa <= depth; sfa++)
+ stack[sfa] = embedvm_pop(vm);
+ embedvm_push(vm, stack[0]);
+ for (sfa = depth; sfa > 0; sfa--)
+ embedvm_push(vm, stack[sfa]);
+ embedvm_push(vm, stack[0]);
+ vm->ip++;
+ break;
+ }
+ if ((opcode & 0x07) == 6) {
+ /* this is a "dig" instruction */
+ uint8_t depth = (opcode >> 3) & 0x07;
+ int16_t stack[depth+2];
+ for (sfa = 0; sfa < depth+2; sfa++)
+ stack[sfa] = embedvm_pop(vm);
+ for (sfa = depth+1; sfa > 0; sfa--)
+ embedvm_push(vm, stack[sfa-1]);
+ embedvm_push(vm, stack[depth+1]);
+ vm->ip++;
+ break;
+ }
+ sfa = ((opcode >> 3) & 0x07) == 4 || ((opcode >> 3) & 0x07) == 5 ? 1 : 0;
+ switch (opcode & 0x07)
+ {
+ case 0:
+ addr = vm->mem_read(vm->ip+1, false, vm->user_ctx) & 0x00ff;
+ vm->ip += 2;
+ break;
+ case 1:
+ addr = vm->mem_read(vm->ip+1, true, vm->user_ctx);
+ vm->ip += 3;
+ break;
+ case 2:
+ addr = embedvm_pop(vm);
+ vm->ip++;
+ break;
+ case 3:
+ addr = (embedvm_pop(vm) << sfa) + (vm->mem_read(vm->ip+1, false, vm->user_ctx) & 0x00ff);
+ vm->ip += 2;
+ break;
+ case 4:
+ addr = (embedvm_pop(vm) << sfa) + vm->mem_read(vm->ip+1, true, vm->user_ctx);
+ vm->ip += 3;
+ break;
+ }
+ switch ((opcode >> 3) & 0x07)
+ {
+ case 0:
+ embedvm_push(vm, vm->mem_read(addr, false, vm->user_ctx) & 0x00ff);
+ break;
+ case 1:
+ vm->mem_write(addr, embedvm_pop(vm), false, vm->user_ctx);
+ break;
+ case 2:
+ embedvm_push(vm, signext(vm->mem_read(addr, false, vm->user_ctx), 0x00ff));
+ break;
+ case 3:
+ vm->mem_write(addr, embedvm_pop(vm), false, vm->user_ctx);
+ break;
+ case 4:
+ embedvm_push(vm, vm->mem_read(addr, true, vm->user_ctx));
+ break;
+ case 5:
+ vm->mem_write(addr, embedvm_pop(vm), true, vm->user_ctx);
+ break;
+ }
+ break;
+ case 0xf0 ... 0xf7:
+ for (sfa = 0; sfa <= (opcode & 0x07); sfa++)
+ embedvm_push(vm, 0);
+ vm->ip++;
+ break;
+ case 0xf8 ... 0xff:
+ a = embedvm_pop(vm);
+ vm->sp += 2 + 2*(opcode & 0x07);
+ embedvm_push(vm, a);
+ vm->ip++;
+ break;
+ }
+}
+
+void embedvm_interrupt(struct embedvm_s *vm, uint16_t addr)
+{
+ embedvm_push(vm, vm->sfp | 1);
+ embedvm_push(vm, vm->ip);
+ vm->sfp = vm->sp;
+ vm->ip = addr;
+}
+
+int16_t embedvm_pop(struct embedvm_s *vm)
+{
+ int16_t value = vm->mem_read(vm->sp, true, vm->user_ctx);
+ vm->sp += 2;
+ return value;
+}
+
+void embedvm_push(struct embedvm_s *vm, int16_t value)
+{
+ vm->sp -= 2;
+ vm->mem_write(vm->sp, value, true, vm->user_ctx);
+}
+
+int16_t embedvm_local_read(struct embedvm_s *vm, int8_t sfa)
+{
+ uint16_t addr = vm->sfp - 2*sfa + (sfa < 0 ? +2 : -2);
+ return vm->mem_read(addr, true, vm->user_ctx);
+}
+
+void embedvm_local_write(struct embedvm_s *vm, int8_t sfa, int16_t value)
+{
+ uint16_t addr = vm->sfp - 2*sfa + (sfa < 0 ? +2 : -2);
+ vm->mem_write(addr, value, true, vm->user_ctx);
+}
+