NS32FV16 Datasheet, PDF (26/104 Pages) Texas Instruments – Advanced Imaging/Communication Signal Processors

2 0 Architectural Description (Continued)
Set Bit String
Set BIT Perpendicular String
Syntax SBITS
Syntax SBITPS
Setup
R0 base address of the destination
R1 starting bit offset (signed)
R2 number of bits to set (unsigned)
R3 address of string look-up table
Setup
R0 base address destination (byte address)
R1 starting bit offset
R2 number of bits to set
R3 destination warp (signed value in bits)
Note When the instruction terminates the registers are returned un-
changed
Note When the instruction terminates the R0 and R3 registers are re-
turned unchanged R1 becomes the final bit offset R2 is zero
SBITS sets a number of contiguous bits in memory to 1 and
The SBITPS can be used to set a string of bits in any direc-
is typically used for data expansion operations The instruc-
tion This allows a font to be expanded with a 90 or 270
tion draws the number of ones specified by the value in R2
degree rotation as may be required in a printer application
starting at the bit address provided by registers R0 and R1
SBITPS sets a string of bits starting at the bit address speci-
In order to maximize speed and allow drawing of patterned
fied in registers R0 and R1 The number of bits in the string
lines an external 1k byte lookup table is used The lookup
is specified in R2 After the first bit is set the destination
table is specified in the NS32CG16 Printer Display Proces-
warp is added to the bit address and the next bit is set The
sor Programmer’s Reference Supplement
When SBITS begins executing it compares the value in R2
with 25 If the value in R2 is less than or equal to 25 the F
flag is cleared and the appropriate number of bits are set in
memory If R2 is greater than 25 the F flag is set and no
other action is performed This allows the software to use a
faster algorithm to set longer strings of bits Figure 2-28
shows the SBITS instruction format
te ²³
15
87
0
000 000 0 0 0 0 1 101 110 0 0 0 1 1 1 0
Obsole ^{FIGURE2-28 SBITSInstructionFormat}
process is repeated until all the bits have been set A nega-
tive raster warp offset value leads to a 90 degree rotation A
positive raster warp value leads to a 270 degree rotation If
the R3 value is e (space warp a1 or b1) then the result is
a 45 degree line If the R3 value is a1 or b1 a horizontal
line results
SBITS and SBITPS allow expansion on any 90 degree an-
gle giving portrait landscape and mirror images from one
font Figure 2-29 shows the SBITPS instruction format
23
15
87
0
000 000 0 0 0 0 1 011 110 0 0 0 1 1 1 0
FIGURE 2-29 SBITPS Instruction Format
FIGURE 2-30 Bus Activity for a Simple BITBLT Operation
Note 1 This example is for a block 4 words wide and 1 line high
Note 2 The sequence is common with all logical operations of the DP8510 DP8511 BPU
Note 3 Mask values shift values and number of bit planes do not affect the performance
Note 4 Zero wait states are assumed throughout the BITBLT operation
Note 5 The extra read is performed when the BPU pipeline register needs to be preloaded
TL EE 11267 – 10
25