From c5dd4897e4d7f45108b6955bebf2d4b5f22a3652 Mon Sep 17 00:00:00 2001
From: "Juan J. Martinez" <jjm@usebox.net>
Date: Tue, 23 May 2023 16:06:46 +0100
Subject: Add cmpi, cmpd, ldi and ldd

---
 vm.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

(limited to 'vm.c')

diff --git a/vm.c b/vm.c
index 72dec72..43a6ab5 100644
--- a/vm.c
+++ b/vm.c
@@ -453,13 +453,90 @@ uint8_t tr8_eval(Tr8 *vm)
                 }
                 break;
 
+            case 14:
+                if (FHL(instr))
+                {
+                    if (FHH(instr))
+                    {
+                        uint8_t f = 0;
+
+                        /* CMPI */
+                        flags(&vm->f, vm->read_m(ADDR(vm->regs[0], vm->regs[2])) - vm->read_m(ADDR(vm->regs[1], vm->regs[3])), ZF | CF | OF | SF);
+
+                        vm->regs[2] = flags(&f, vm->regs[2] + 1, OF);
+                        if (f & OF)
+                            vm->regs[0]++;
+
+                        vm->regs[3] = flags(&f, vm->regs[3] + 1, OF);
+                        if (f & OF)
+                            vm->regs[1]++;
+
+                        vm->icnt += 3;
+                    }
+                    else
+                    {
+                        uint8_t f = 0;
+
+                        /* CMPD */
+                        flags(&vm->f, vm->read_m(ADDR(vm->regs[0], vm->regs[2])) - vm->read_m(ADDR(vm->regs[1], vm->regs[3])), ZF | CF | OF | SF);
+
+                        vm->regs[2] = flags(&f, vm->regs[2] - 1, OF);
+                        if (f & OF)
+                            vm->regs[0]--;
+
+                        vm->regs[3] = flags(&f, vm->regs[3] - 1, OF);
+                        if (f & OF)
+                            vm->regs[1]--;
+
+                        vm->icnt += 3;
+                    }
+                }
+                else
+                {
+                    if (FHH(instr))
+                    {
+                        uint8_t f = 0;
+
+                        /* LDI */
+                        vm->write_m(ADDR(vm->regs[1], vm->regs[3]), vm->read_m(ADDR(vm->regs[0], vm->regs[2])));
+
+                        vm->regs[2] = flags(&f, vm->regs[2] + 1, OF);
+                        if (f & OF)
+                            vm->regs[0]++;
+
+                        vm->regs[3] = flags(&f, vm->regs[3] + 1, OF);
+                        if (f & OF)
+                            vm->regs[1]++;
+
+                        vm->icnt += 3;
+                    }
+                    else
+                    {
+                        uint8_t f = 0;
+
+                        /* LDD */
+                        vm->write_m(ADDR(vm->regs[1], vm->regs[3]), vm->read_m(ADDR(vm->regs[0], vm->regs[2])));
+
+                        vm->regs[2] = flags(&f, vm->regs[2] - 1, OF);
+                        if (f & OF)
+                            vm->regs[0]--;
+
+                        vm->regs[3] = flags(&f, vm->regs[3] - 1, OF);
+                        if (f & OF)
+                            vm->regs[1]--;
+
+                        vm->icnt += 3;
+                    }
+                }
+                break;
+
             default:
                 fprintf(stderr, "*invalid opcode 0x%01x at PC=0x%04x*\n", (instr >> 12), 2 * (vm->pc - 1));
                 tr8_dump(vm, stderr);
                 return 1;
         }
 
-        if (vm->icnt == INSTR_PER_FRAME)
+        if (vm->icnt >= INSTR_PER_FRAME)
             return 1;
     }
 }
-- 
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