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MOTOROLA M68040 USER’S MANUAL 9- 47
Table 9-16. State Frame Field Information (Concluded)
FSAVE State
Frame Field Contents
INEX (FMOVE to Register, FABS, and FNEG)
CMDREG1B Exception Instruction Command Word
FPTEMP Unrounded, Extended-Precision Intermediate Result
STAG Source Operand Tag = Normalized
E1 Always 1
T Always 0
INEX (FADD, FSUB, FMUL, FDIV, and FSQRT)
CMDREG3B Encoded Exception Instruction Command Word
WBTEMP WBTS, WBTE, and WBTM = intermediate result sign, biased 15-bit
exponent, and 64-bit mantissa prior to rounding.
WBTE15 Either 1 or 0, generally useless for INEX exceptions.
WBTM1, WBTM0,
SBIT
Guard, round, and sticky of intermediate result’s 67-bit mantissa.
E3 Always 1
T Either 1 or 0
INEX (FMOVE to Memory)
CMDREG1B FMOVE Instruction Command Word
FPTEMP Intermediate result with mantissa prior to rounding.
STAG Source Operand Tag = Normalized
E1 Always 1
T Always 1
NOTE: If the M68040FPSP unimplemented exception handler is used, the above state frame
information applies. The CMDREG1B or CMDREG3B fields of the state frame are modified as
appropriate to encode the unimplemented instruction opcode. It is the user exception handler’s
responsibility to use the E3 and E1 field encodings to recognize which state frame information
applies. When E3 = 1 and E1 = 1, E3 takes priority and the state frame information for E3 = 1
must be used.
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