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2.0 KiB
2.0 KiB
The PowerPC is the main processor behind Power Macs.
General Notes
All instructions are 32 bits wide, regardless of whether the PowerPC is in 32-bit or 64-bit mode.
Code execution generally begins at 0xFFF00100, which the reset exception vector.
BATs
The 601 BATs are emulated by the OpenFirmware.
Processor Revisions
| Model | PVR Number | Notable Aspects |
|---|---|---|
| 601 | 0x00010001 | Supports POWER instructions |
| 603 | 0x00030001 | Software-controlled TLBs |
| 604 | 0x00040103 | Ability for Multiprocessing |
| 603E | 0x00060101 | |
| 750 (G3) | 0x00080200 | Built-in L2 data cache |
| 7400 (G4) | 0x000C0101 | AltiVec/VMX support added |
Registers
| Register Type | Number | Purpose |
|---|---|---|
| General Purpose (GPR) | 32 | Calculate, Store, and Load 32-bit fixed-point numbers |
| Floating Point (FPR) | 32 | Calculate, Store, and Load 32-bit or 64-bit floating-point numbers |
| Special Purpose (SPR) | Up to 1024 (in theory) | Store and load specialized 32-bit fixed-point numbers |
| Segment (SR) | 16 | Calculate, Store, and Load 32-bit fixed-point numbers |
| Time Base Facility (TBR) | 2 | Calculate, Store, and Load 32-bit fixed-point numbers |
| Condition Register | 1 | Stores conditions based on the results of fixed-point operations |
| Floating Point Condition Register | 1 | Stores conditions based on the results of floating-point operations |
| Machine State Register | 1 |