under Contract DABT63-95-C-0127 and ARPA order no. D346. The current support for this work comes from a variety of sources, all of to which we are indebted.

CVT.W.S:Opcode:Format:Semantics:

CVT.W.D:Opcode:Format:Semantics:

C.EQ.S:Opcode:Format:Semantics:

C.EQ.D:Opcode:Format:Semantics:

C.LT.S:Opcode:Format:Semantics:

C.LT.D:Opcode:Format:Semantics:

C.LE.S:Opcode:Format:Semantics:

C.LE.D:Opcode:Format:Semantics:

SQRT.S:Opcode:Format:Semantics:

FPALIGN(FS)

SET_FPR_D(FD,(double)FPR_L(FS))

Convert single precision to integer.0x84

CVT.W.S fd,fs

FPALIGN(FD)FPALIGN(FS)

SET_FPR_L(FD, (long)FPR_F(FS))

Convert double precision to integer.0x85

CVT.W.D fd,fs

FPALIGN(FD)FPALIGN(FS)

SET_FPR_L(FD, (long)FPR_D(FS))

Test if equal, single precision.0x90

C.EQ.S fs,ft

FPALIGN(FS)FPALIGN(FT)

SET_FCC(FPR_F(FS) == FPR_F(FT))

Test if equal, double precision.0x91

C.EQ.D fs,ft

FPALIGN(FS)FPALIGN(FT)

SET_FCC(FPR_D(FS) == FPR_D(FT))

Test if less than, single precision.0x92

C.LT.S fs,ft

FPALIGN(FS)FPALIGN(FT)

SET_FCC(FPR_F(FS) < FPR_F(FT))

Test if less than, double precision.0x93

C.LT.D fs,ft

FPALIGN(FS)FPALIGN(FT)

SET_FCC(FPR_D(FS) < FPR_D(FT))

Test if less than or equal, single precision.0x94

C.LE.S fs,ft

FPALIGN(FS)FPALIGN(FT)

SET_FCC(FPR_F(FS) <= FPR_F(FT))

Test if less than or equal, double precision.0x95

C.LE.D fs,ft

FPALIGN(FS)FPALIGN(FT)

SET_FCC(FPR_D(FS) <= FPR_D(FT))

Square root, single precision.0x96

SQRT.S fd,fs

FPALIGN(FD)

SET_FPR_F(FD,sqrt((double)FPR_F(FS)))

SQRT.D:Square root, double precision.Opcode:0x97

Format:SQRT.D fd,fs

Semantics:

FPALIGN(FD)FPALIGN(FS)

SET_FPR_D(FD, sqrt(FPR_D(FS)))

A.5 Miscellaneous instructions

NOP:

No operation.Opcode:0x00Format:NOPSemantics:None

SYSCALL:System call.Opcode:0xa0

Format:SYSCALL

Semantics:See AppendixB for details

BREAK:Declare a program error.Opcode:0xa1

Format:BREAK uimm

Semantics:

Actions are simulator-dependent. Typically,an error message is printed andabort() iscalled.

LUI:

Load upper immediate.Opcode:0xa2

Format:LUI uimm

Semantics:SET_GPR(RT, UIMM << 16)

MFC1:Move from oating point to integer register le.Opcode:0xa3

Format:MFC1 rt,fs

Semantics:SET_GPR(RT, FPR_L(FS))

MTC1:Move from integer to oating point register le.Opcode:0xa5

Format:MTC1 rt,fs

Semantics:

SET_FPR_L(FS, GPR(RT))

B System call de nitions

This appendix lists all system calls supported by the simula-tors with their system call code (syscode), interface speci cation,and appropriate POSIX Unix reference. Systems calls are initi-ated with the SYSCALL instruction. Prior to execution of aSYSCALL instruction, register $v0 should be loaded with thesystem call code. The arguments of the system call interface pro-totype should be loaded into registers $a0 - $a3 in the order spec-i ed by the system call interface prototype,e.g., for:

read(int fd, char *buf, int nbyte),

0x03 is loaded into $v0,fd is loaded into $a0,buf into $a1, andnbyte into $a2.EXIT:

Exit process.