SWRU543B January 2019 – June 2025 CC3230S , CC3230SF , CC3235MODS , CC3235MODSF , CC3235S , CC3235SF
The procedure in Table 19-7 continues a prior HMAC calculation interrupted from a high priority task.
| Step | Register/Bit Field/Programming Model | Value |
|---|---|---|
| Load the initial digest for the used hash algorithm. | SHAMD5_IDIGEST_i[31:0] DATA | – |
| Restore the digest counter with the value before the switch to the high-priority task. | SHAMD5_DIGEST_COUNT[31:0] COUNT | – |
| Use the already loaded in the engine key. | SHAMD5_MODE[5] HMAC_KEY_PROC | 0x0 |
| Do not use the constants of the selected hash algorithm. | SHAMD5_MODE[3] ALGO_CONSTANT | 0x0 |
| Select the SHA-1 hash algorithm. | SHAMD5_MODE[2:1] ALGO | 0x1 |
| IF: This is the last 64-byte data block from the input message? | User decision | |
| Close the hash; an appropriate padding is added. | SHAMD5_MODE[4] CLOSE_HASH | 0x1 |
| ENDIF | ||
| Load the block length; this is the trigger to start processing. | SHAMD5_LENGTH[31:0] LENGTH | – |
This initial digest is the intermediate digest from the previous calculation before switching to the high priority task. The value is equal to context1 in . Ref to Figure 19-3?
The value is equal to context2 in . Ref to Figure 19-3?
The block length is equal to the context3 value in . Ref to Figure 19-3?