Resizable BAR Capability Register 0 @0x184
This register advertises the available aperture settings of the first memory BAR of the associated Physical Function. This register is active only when the Resizable BAR Capability is enabled for the Physical Function by setting the Enable Resizable BAR Capability (bit 31) of the associated Physical Function BAR Configuration Register 1. When the Resizable BAR Capability is not enabled, a read from this location returns all zeros. When the Resizable BAR Capability is enabled, any of the bits 4–22 can be modified from the local management bus.
| Bits | SW | Name | Description | Reset |
|---|---|---|---|---|
| 3:0 | R | Reserved [R0] | Reserved | 0x0 |
| 4 | R/W | Aperture 1M [A1M] | Indicates that the BAR aperture can be set to 1M. | 0x0 |
| 5 | R/W | Aperture 2M [A2M] | Indicates that the BAR aperture can be set to 2M. | 0x0 |
| 6 | R/W | Aperture 4M [A4M] | Indicates that the BAR aperture can be set to 4M. | 0x0 |
| 7 | R/W | Aperture 8M [A8M] | Indicates that the BAR aperture can be set to 8M. | 0x0 |
| 8 | R/W | Aperture 16M [A16M] | Indicates that the BAR aperture can be set to 16M. | 0x0 |
| 9 | R/W | Aperture 32M [A32M] | Indicates that the BAR aperture can be set to 32M. | 0x0 |
| 10 | R/W | Aperture 64M [A64M] | Indicates that the BAR aperture can be set to 64M. | 0x0 |
| 11 | R/W | Aperture 128M [A128M] | Indicates that the BAR aperture can be set to 128M. | 0x0 |
| 12 | R/W | Aperture 256M [A256M] | Indicates that the BAR aperture can be set to 256M. | 0x0 |
| 13 | R/W | Aperture 512M [A512M] | Indicates that the BAR aperture can be set to 512M. | 0x0 |
| 14 | R/W | Aperture 1G [A1G] | Indicates that the BAR aperture can be set to 1G. | 0x0 |
| 15 | R/W | Aperture 2G [A2G] | Indicates that the BAR aperture can be set to 2G. | 0x0 |
| 16 | R/W | Aperture 4G [A4G] | Indicates that the BAR aperture can be set to 4G. | 0x0 |
| 17 | R/W | Aperture 8G [A8G] | Indicates that the BAR aperture can be set to 8G. | 0x0 |
| 18 | R/W | Aperture 16G [A16G] | Indicates that the BAR aperture can be set to 16G. | 0x0 |
| 19 | R/W | Aperture 32G [A32G] | Indicates that the BAR aperture can be set to 32G. | 0x0 |
| 20 | R/W | Aperture 64G [A64G] | Indicates that the BAR aperture can be set to 64G. | 0x0 |
| 21 | R/W | Aperture 128G [A128G] | Indicates that the BAR aperture can be set to 128G. | 0x0 |
| 22 | R/W | Aperture 256G [A256G] | Indicates that the BAR aperture can be set to 256G. | 0x0 |
| 23 | R/W | Aperture 512G [A512G] | Indicates that the BAR aperture can be set to 512G. | 0x0 |
| 31:24 | R | Reserved [R1] | Reserved | 0x0 |