VAX Floating-Point Instructions

Programming Note:

In order to use CMPTxx with software completion trap handling, it is necessary to specify the /SU IEEE trap mode, even though an underflow trap is not possible. In order to use CVTQS or CVTQT with software completion trap handling, it is necessary to specify the /SUI IEEE trap mode, even though an underflow trap is not possible.

A.4 VAX Floating-Point Instructions

Table A–6lists the hexadecimal value of the 11-bit function code field for the VAX floating-point instructions. The opcode for these instructions is 1516.

Table A–6 VAX Floating-Point Instruction Function Codes

MnemonicNone /C /U /UC /S /SC /SU /SUC

ADDF

080

000

180

100

480

400

580

500

ADDG

0A0

020

1A0

120

4A0

420

5A0

520

CMPGEQ

0A5

 

 

 

4A5

 

 

 

CMPGLE

0A7

 

 

 

4A7

 

 

 

CMPGLT

0A6

 

 

 

4A6

 

 

 

CVTDG

09E

01E

19E

11E

49E

41E

59E

51E

CVTGD

0AD

02D

1AD

12D

4AD

42D

5AD

52D

CVTGF

0AC

02C

1AC

12C

4AC

42C

5AC

52C

CVTGQ

See below

 

 

 

 

 

 

 

CVTQF

0BC

03C

 

 

 

 

 

 

CVTQG

0BE

03E

 

 

 

 

 

 

DIVF

083

003

183

103

483

403

583

503

DIVG

0A3

023

1A3

123

4A3

423

5A3

523

MULF

082

002

182

102

482

402

582

502

MULG

0A2

022

1A2

122

4A2

422

5A2

522

SQRTF

08A

00A

18A

10A

48A

40A

58A

50A

SQRTG

0AA

02A

1AA

12A

4AA

42A

5AA

52A

SUBF

081

001

181

101

481

401

581

501

SUBG

0A1

021

1A1

121

4A1

421

5A1

521

 

 

 

 

 

 

 

 

 

Mnemonic

None

/C

/V

/VC

/S

/SC

/SV

/SVC

 

 

 

 

 

 

 

 

 

CVTGQ

0AF

02F

1AF

12F

4AF

42F

5AF

52F

 

 

 

 

 

 

 

 

 

A.5 Independent Floating-Point Instructions

Table A–7lists the hexadecimal value of the 11-bit function code field for the floating- point instructions that are not directly tied to IEEE or VAX floating point. The opcode for the following instructions is 1716.

21264/EV68A Hardware Reference Manual

Alpha Instruction Set A–11

Page 275
Image 275
Compaq EV68A specifications VAX Floating-Point Instructions, Independent Floating-Point Instructions