ia-32_instruction-set-ref_a-m

Zf pf and cf in the eflags register according to the

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Unformatted text preview: , C3 Set to 0 if stack underflow occurred; otherwise, set to 0. Not affected. Floating-Point Exceptions #IS #IA Stack underflow occurred. (FCOMI or FCOMIP instruction) One or both operands are NaN values or have unsupported formats. (FUCOMI or FUCOMIP instruction) One or both operands are SNaN values (but not QNaNs) or have undefined formats. Detection of a QNaN value does not raise an invalid-operand exception. Protected Mode Exceptions #NM #MF CR0.EM[bit 2] or CR0.TS[bit 3] = 1. If there is a pending x87 FPU exception. Real-Address Mode Exceptions Same exceptions as in Protected Mode. Virtual-8086 Mode Exceptions Same exceptions as in Protected Mode. Compatibility Mode Exceptions Same exceptions as in Protected Mode. 64-Bit Mode Exceptions Same exceptions as in Protected Mode. Vol. 2 3-309 INSTRUCTION SET REFERENCE, A-M FCOS--Cosine Opcode D9 FF Instruction FCOS 64-Bit Mode Valid Compat/ Leg Mode Valid Description Replace ST(0) with its cosine. Description Computes the cosine of the source operand in register ST(0) and stores the result in ST(0). The source operand must be given in radians and must be within the range - 263 to +263. The following table shows the results obtained when taking the cosine of various classes of numbers. Table 3-28. FCOS Results ST(0) SRC - -F ST(0) DEST * -1 to +1 +1 +1 -1 to +1 * NaN -0 +0 +F + NaN NOTES: F Means finite floating-point value. * Indicates floating-point invalid-arithmetic-operand (#IA) exception. 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 out-of-range 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 IA-32 Architectures Software Developer's Manual, Volume 1, for a discussion of the proper value to use for in performing such reductions. This instruction's operation is the same in non-64-bit modes and 64-bit mode. 3-310 Vol. 2 INSTRUCTION SET REFERENCE, A-M Operation IF |ST(0)| < 263 THEN C2 0; ST(0) cosine(ST(0)); ELSE (* Source operand is out-of-range *) C2 1; FI; FPU Flags Affected C1 Set to 0 if stack underflow occurred. Set if result was rounded up; cleared otherwise. Undefined if C2 is 1. C2 C0, C3 Set to 1 if outside range (-263 < source operand < +263); otherwise, set to 0. Undefined. Floating-Point Exceptions #IS #IA #D #P Stack underflow occurred. Source operand is an SNaN value, , or unsupported format. Source is a denormal value. Value cannot be represented exactly in 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. Real-Address Mode Exceptions...
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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.

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