Difference between revisions of "83Plus:BCALLs:8090"

Revision as of 18:31, 27 March 2005

Synopsis

Official Name: MD5Update

Other Name: CalculateMD5

BCALL Address: 8090

Calculates the MD5 checksum

Inputs

• BC: The length of the data
• HL: The location of the data

Outputs

• 8269: (8 bytes) Holds the length in bits of the data hashed so far.
• 8292: (16 bytes) Will be changed to contain the new (incremental) MD5 hash of the data you gave it

Destroys

• 8259: (16 bytes) Alternate registers (roughly equivalent to the AA, BB, CC, and DD registers specified in the MD5 standard.)
• 83A5: (64 bytes) Buffer holding data to be hashed.

Comments

This B_CALL incrementally changes the MD5 "registers" for the data you give it. Note that the registers must be initialized using 808D first. You can call this B_CALL as many times as you want to add many separate chunks of data to the hash. To complete the MD5 hash, use 8018.

Example

B_CALL InitializeMD5
ld bc,0040h
ld hl,SomeAddress
B_CALL CalculateMD5
B_CALL FinishMD5

Credits and Contributions

• FloppusMaximus: For testing that this B_CALL also work with lengths unequal to 64 bytes