NAME

HsiDecompSetup− set up HSI for decompression
HsiLoadTokenRAM− load HSI decompression token RAM table
HsiLoadMappingRAM− load HSI decompression mapping RAM table

SYNOPSIS

#include <hsidefs.h>
#include <yapdefs.h>

int HsiDecompSetup(hsi, nlines, format, rcvaddr)
HSIDEV ∗hsi;
int nlines, format, rcvaddr;

void HsiLoadTokenRAM(hsi, ttn, chan, ramp)
HSIDEV ∗hsi;
int ttn, chan;
unsigned short ∗ramp;

void HsiLoadMappingRAM(hsi, chan, ramp)
HSIDEV ∗hsi;
int chan;
unsigned short ∗ramp;

DESCRIPTION

The routines described here require that the optional decompression hardware be installed with the Pixar HSI. 

HsiDecompSetup prepares the HSI for decompressing data and sending the results to the yapbus.  Decompressed pixels will be sent to the yapbus in nlines lines of 1024 pixels each.  Every 2624 bytes of compressed data written to the data window yields one line of 1024 decompressed pixels.  format is either 0 or HSI_FMT_REORDER.  rcvaddr specifies the yapbus address used by the receiving Chap.  Prior to calling HsiDecompSetup, a Chap routine (for example, YSCopy) must be started to send or receive data from the HSI.  After calling HsiDecompSetup, the application program writes compressed data to the HSI data window. After all data has been sent to the HSI, the application should call HsiWaitDone to wait for the HSI to report completion of the service, and then it should call HsiGetStatus to obtain the completion status of the transfer. 

HsiLoadTokenRAM loads values into the decompression token RAM table.  ttn is a token table number, from 0 to 31.  chan is a channel number, from 0 to 3.  ramp points to the first element of a 32-element array of 12-bit delta values (the high-order 4 bits of each array element are not used). 

HsiLoadMappingRAM loads values into the decompression mapping RAM table.  chan is a channel number, from 0 to 3.  ramp points to the first element of a 4096-element array of 16-bit values. 

RETURN VALUE

Upon successful setup, HsiDecompSetup returns 0.  If an error (invalid parameter or decompression hardware not present) is detected, HsiDecompSetup returns −1, and a subsequent call to HsiGetStatus(3H) will return a specific error code in the hst_error field of the hsi_status structure. 

SEE ALSO

HsiGetStatus(3H), HsiOpen(3H), HsiSetup(3H)

HSI Tutorial

Sun Release 4.1  —  Last change: