ia-32_instruction-set-ref_a-m

Floating point values in the source operand second

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Unformatted text preview: ] = 1. If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:EDX.SSE[bit 25] = 0. Vol. 2 3-61 INSTRUCTION SET REFERENCE, A-M Real-Address Mode Exceptions #GP(0) If a memory operand is not aligned on a 16-byte boundary, regardless of segment. If any part of the operand lies outside the effective address space from 0 to FFFFH. #NM #UD If CR0.TS[bit 3] = 1. If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:EDX.SSE[bit 25] = 0. Virtual-8086 Mode Exceptions Same exceptions as in Real Address Mode #PF(fault-code) For a page fault. Compatibility Mode Exceptions Same exceptions as in Protected Mode. 64-Bit Mode Exceptions #SS(0) #GP(0) If a memory address referencing the SS segment is in a noncanonical form. If the memory address is in a non-canonical form. If memory operand is not aligned on a 16-byte boundary, regardless of segment. #PF(fault-code) #NM #UD For a page fault. If CR0.TS[bit 3] = 1. If CR0.EM[bit 2] = 1. If CR4.OSFXSR[bit 9] = 0. If CPUID.01H:EDX.SSE[bit 25] = 0. 3-62 Vol. 2 INSTRUCTION SET REFERENCE, A-M ARPL--Adjust RPL Field of Segment Selector Opcode 63 /r Instruction ARPL r/m16, r16 64-Bit Mode N. E. Compat/ Leg Mode Valid Description Adjust RPL of r/m16 to not less than RPL of r16. Description Compares the RPL fields of two segment selectors. The first operand (the destination operand) contains one segment selector and the second operand (source operand) contains the other. (The RPL field is located in bits 0 and 1 of each operand.) If the RPL field of the destination operand is less than the RPL field of the source operand, the ZF flag is set and the RPL field of the destination operand is increased to match that of the source operand. Otherwise, the ZF flag is cleared and no change is made to the destination operand. (The destination operand can be a word register or a memory location; the source operand must be a word register.) The ARPL instruction is provided for use by operating-system procedures (however, it can also be used by applications). It is generally used to adjust the RPL of a segment selector that has been passed to the operating system by an application program to match the privilege level of the application program. Here the segment selector passed to the operating system is placed in the destination operand and segment selector for the application program's code segment is placed in the source operand. (The RPL field in the source operand represents the privilege level of the application program.) Execution of the ARPL instruction then insures that the RPL of the segment selector received by the operating system is no lower (does not have a higher privilege) than the privilege level of the application program (the segment selector for the application program's code segment can be read from the stack following a procedure call). This instruction executes as described in compatibility mode and legacy mode. It is not encodable in 64-bit mode. See "Checking Caller Access Privileges" in Chapt...
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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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