Broadway/Registers
On this page you can find a description of some of the registers available in the "Broadway" CPU. The "Broadway" CPU is an enhanced version of the "Gekko" CPU developed for the Nintendo GameCube videoconsole, which is based on the PowerPC 750CXe CPU design.
Special Purpose Registers (SPRs)
Most of these registers are already present on 750CX or Gekko. Others seem to be new (like HID4).
| Name | Number | Description |
|---|---|---|
| GQR0 | 912 (0x390) | Graphics Quantization Register 0 |
| GQR1 | 913 (0x391) | Graphics Quantization Register 1 |
| GQR2 | 914 (0x392) | Graphics Quantization Register 2 |
| GQR3 | 915 (0x393) | Graphics Quantization Register 3 |
| GQR4 | 916 (0x394) | Graphics Quantization Register 4 |
| GQR5 | 917 (0x395) | Graphics Quantization Register 5 |
| GQR6 | 918 (0x396) | Graphics Quantization Register 6 |
| GQR7 | 919 (0x397) | Graphics Quantization Register 7 |
| HID0 | 1008 (0x3F0) | Hardware Implementation-Dependent register 0 |
| HID1 | 1009 (0x3F1) | Hardware Implementation-Dependent register 1 |
| HID2 | 920 (0x398) | Hardware Implementation-Dependent register 2 |
| HID4 | 1011 (0x3F3) | Hardware Implementation-Dependent register 4 |
| L2CR | 1017 (0x3F9) | Layer 2 cache Control Register |
| MMCR0 | 952 (0x3B8) | Monitor Mode Control Register 0 |
| MMCR1 | 956 (0x3BC) | Monitor Mode Control Register 1 |
| PMC1 | 953 (0x3B9) | Performance Monitor Counter register 1 |
| PMC2 | 954 (0x3BA) | Performance Monitor Counter register 2 |
| PMC3 | 957 (0x3BD) | Performance Monitor Counter register 3 |
| PMC4 | 958 (0x3BE) | Performance Monitor Counter register 4 |
| WPAR | 921 (0x399) | Write-gather Pipe Address Register |
| ... | ... | ... |
HID0
Bit 28 (0x8) seems to be related to instruction syncs; PPCSync enables this, runs sync, and restores the old value.
HID2
Bit 30 (second most significant) determines whether paired singles should be stored by Revolution OS on context switch.
HID4
Bit 31 (most significant bit) is H4A (unknown purpose). The "Broadway" CPU seems to have a bug which makes unreliable to clear this bit, as noted in some strings in the SDK.