diff options
| -rw-r--r-- | engines/sci/engine/vm.cpp | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/engines/sci/engine/vm.cpp b/engines/sci/engine/vm.cpp index 3d320d485c..e636935908 100644 --- a/engines/sci/engine/vm.cpp +++ b/engines/sci/engine/vm.cpp @@ -87,8 +87,10 @@ static StackPtr validate_stack_addr(EngineState *s, StackPtr sp) { static int validate_arithmetic(reg_t reg) { if (reg.segment) { + // When using a pointer in number arithmetic, we substitute a large value as + // some scripts rely on this (cf. Hoyle hack in kAbs). warning("[VM] Attempt to read arithmetic value from non-zero segment [%04x]", reg.segment); - return 0; + return 0x3e9; } return reg.offset; @@ -97,7 +99,7 @@ static int validate_arithmetic(reg_t reg) { static int signed_validate_arithmetic(reg_t reg) { if (reg.segment) { warning("[VM] Attempt to read arithmetic value from non-zero segment [%04x]", reg.segment); - return 0; + return 0x3e9; } if (reg.offset & 0x8000) @@ -890,25 +892,37 @@ void run_vm(EngineState *s, int restoring) { case 0x13: // ugt? s->r_prev = s->r_acc; r_temp = POP32(); - s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset > s->r_acc.offset); + if (r_temp.segment && s->r_acc.segment) + s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset > s->r_acc.offset); + else + s->r_acc = ACC_ARITHMETIC_L(validate_arithmetic(r_temp) > /*acc*/); break; case 0x14: // uge? s->r_prev = s->r_acc; r_temp = POP32(); - s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset >= s->r_acc.offset); + if (r_temp.segment && s->r_acc.segment) + s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset >= s->r_acc.offset); + else + s->r_acc = ACC_ARITHMETIC_L(validate_arithmetic(r_temp) >= /*acc*/); break; case 0x15: // ult? s->r_prev = s->r_acc; r_temp = POP32(); - s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset < s->r_acc.offset); + if (r_temp.segment && s->r_acc.segment) + s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset < s->r_acc.offset); + else + s->r_acc = ACC_ARITHMETIC_L(validate_arithmetic(r_temp) < /*acc*/); break; case 0x16: // ule? s->r_prev = s->r_acc; r_temp = POP32(); - s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset <= s->r_acc.offset); + if (r_temp.segment && s->r_acc.segment) + s->r_acc = make_reg(0, (r_temp.segment == s->r_acc.segment) && r_temp.offset <= s->r_acc.offset); + else + s->r_acc = ACC_ARITHMETIC_L(validate_arithmetic(r_temp) <= /*acc*/); break; case 0x17: // bt |