Unformatted text preview: lue, modulus (divisor) is 0, dividend is , or unsupported format. Source operand is a denormal value. Result is too small for destination format. Protected Mode Exceptions
#NM #MF CR0.EM[bit 2] or CR0.TS[bit 3] = 1. If there is a pending x87 FPU exception. RealAddress Mode Exceptions
Same exceptions as in Protected Mode. Virtual8086 Mode Exceptions
Same exceptions as in Protected Mode. Compatibility Mode Exceptions
Same exceptions as in Protected Mode. 64Bit Mode Exceptions
Same exceptions as in Protected Mode. 3362 Vol. 2 INSTRUCTION SET REFERENCE, AM FPTANPartial Tangent
Opcode D9 F2 Instruction FPTAN 64Bit Mode Valid Compat/ Leg Mode Valid Description Replace ST(0) with its tangent and push 1 onto the FPU stack. Description
Computes the tangent of the source operand in register ST(0), stores the result in ST(0), and pushes a 1.0 onto the FPU register stack. The source operand must be given in radians and must be less than 263. The following table shows the unmasked results obtained when computing the partial tangent of various classes of numbers, assuming that underflow does not occur. Table 338. FPTAN Results
ST(0) SRC
 F ST(0) DEST * F to +F
0 0 +0 +F + NaN NOTES: F Means finite floatingpoint value. * Indicates floatingpoint invalidarithmeticoperand (#IA) exception. +0 F to +F *
NaN If the source operand is outside the acceptable range, the C2 flag in the FPU status word is set, and the value in register ST(0) remains unchanged. The instruction does not raise an exception when the source operand is out of range. It is up to the program to check the C2 flag for outofrange conditions. Source values outside the range 263 to +263 can be reduced to the range of the instruction by subtracting an appropriate integer multiple of 2 or by using the FPREM instruction with a divisor of 2. See the section titled "Pi" in Chapter 8 of the Intel 64 and IA32 Architectures Software Developer's Manual, Volume 1, for a discussion of the proper value to use for in performing such reductions. The value 1.0 is pushed onto the register stack after the tangent has been computed to maintain compatibility with the Intel 8087 and Intel287 math coprocessors. This operation also simplifies the calculation of other trigonometric functions. For Vol. 2 3363 INSTRUCTION SET REFERENCE, AM instance, the cotangent (which is the reciprocal of the tangent) can be computed by executing a FDIVR instruction after the FPTAN instruction. This instruction's operation is the same in non64bit modes and 64bit mode. Operation
IF ST(0) < 263 THEN C2 0; ST(0) tan(ST(0)); TOP TOP  1; ST(0) 1.0; ELSE (* Source operand is outofrange *) C2 1; FI; FPU Flags Affected
C1 Set to 0 if stack underflow occurred; set to 1 if stack overflow occurred. Set if result was rounded up; cleared otherwise. C2 C0, C3 Set to 1 if outside range (263 < source operand < +263); otherwise, set to 0. Undefined. FloatingPoint Exceptions
#IS #IA #D #U #P Stack underflow...
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This note was uploaded on 10/01/2013 for the course CPE 103 taught by Professor Watlins during the Winter '11 term at Mississippi State.
 Winter '11
 Watlins

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