===========================================================================
| 487 | |
| 488 | //=========================================================================== |
| 489 | bool _6502_CalcRelativeOffset ( int nOpcode, int nBaseAddress, int nTargetAddress, WORD * pTargetOffset_ ) |
| 490 | { |
| 491 | if (_6502_IsOpcodeBranch(nOpcode)) |
| 492 | { |
| 493 | // Branch is |
| 494 | // a) relative to address+2 |
| 495 | // b) in 2's compliment |
| 496 | // |
| 497 | // i.e. |
| 498 | // 300: D0 7F -> BNE $381 0x381 - 0x300 = 0x81 +129 |
| 499 | // 300: D0 80 -> BNE $282 0x282 - 0x300 = -126 |
| 500 | // |
| 501 | // 300: D0 7E BNE $380 |
| 502 | // ^ ^ ^ ^ |
| 503 | // | | | TargetAddress |
| 504 | // | | TargetOffset |
| 505 | // | Opcode |
| 506 | // BaseAddress |
| 507 | int nDistance = nTargetAddress - nBaseAddress; |
| 508 | if (pTargetOffset_) |
| 509 | *pTargetOffset_ = (BYTE)(nDistance - 2); |
| 510 | |
| 511 | if ((nDistance - 2) > _6502_BRANCH_POS) |
| 512 | m_iAsmAddressMode = NUM_OPMODES; // signal bad |
| 513 | |
| 514 | if ((nDistance - 2) < _6502_BRANCH_NEG) |
| 515 | m_iAsmAddressMode = NUM_OPMODES; // signal bad |
| 516 | |
| 517 | return true; |
| 518 | } |
| 519 | |
| 520 | return false; |
| 521 | } |
| 522 | |
| 523 | //=========================================================================== |
| 524 | int _6502_GetOpmodeOpbyte ( const int nBaseAddress, int & iOpmode_, int & nOpbyte_, const DisasmData_t** pData_ ) |
no test coverage detected