GXM datasheet(234/244 Pages) NSC

234 / 244 page

www.national.com

234

Revision 3.1

Instruction Set (Continued)

9.6

NATIONAL SEMICONDUCTOR EXTENDED MMX INSTRUCTION SET

National Semiconductor has added instructions to its

implementation of the MMX Architecture in order to facili-

tate writing of multimedia applications. In general, these

instructions allow more efficient implementation of multi-

media algorithms, or more precision in computation than

can be achieved using the basic set of MMX instructions.

All of the added instructions follow the SIMD (single

instruction, multiple data) format. Many of the instructions

add flexibility to the MMX architecture by allowing both

source operands of an instruction to be preserved, while

the result goes to a separate register that is derived from

the input.

Table 9-33 on page 235 summarizes the Extended MMX

Instructions. The abbreviations used in the table are listed

in Table 9-32.

Configuration control register CCR7(0) at location EBh

must be set to allow the execution of the Extended MMX

instructions.

Table 9-32. Extend MMX Instruction Set Table

Legend

Abbreviation

Description

<----

Result written

[11 mm reg]

Binary or binary groups of digits

One of eight 64-bit MMX registers

reg

A general purpose register

<--sat--

If required, the resultant data is saturated

to remain in the associated data range

<--move--

Source data is moved to result location

[byte]

Eight 8-bit bytes are processed in parallel

[word]

Four 16-bit WORD are processed in paral-

lel

[dword]

Two 32-bit DWORDs are processed in par-

allel

[qword]

One 64-bit QWORD is processed

[sign xxx]

The BYTE, WORD, DWORD or QWORD

most significant bit is a sign bit

mm1, mm2

MMX Register 1, MMX Register 2

mod r/m

Mod and r/m byte encoding (page 6-6 of

this manual)

pack

Source data is truncated or saturated to

next smaller data size, then concatenated.

packdw

Pack two DWORDs from source and two

DWORDs from destination into four

WORDs in destination register.

packwb

Pack four WORDs from source and four

WORDs from destination into eight BYTEs

in destination register.

GXM датащи(PDF) 234 Page - National Semiconductor (TI)

GXM датащи(HTML) 234 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

датащи скачать

ссылки URL