section 7 - Index of

section 7 - Index of section 7 - Index of

11.07.2015 Views

JccJump ConditionallyJccOperation:If cc, then Oxxx -+PCelse PC+ 1 -+PCIf cc, then ea -+PCelse PC+ 1 -+PCAssem bier Syntax:Jcc xxxJcc xxxDescription: Jump to the location in program memory given by the instruction's effectiveaddress if the specified condition is true. If the specified condition is false, the programcounter (PC) is incremented and the effective address is ignored. However, the addressregister specified in the effective address field is always updated independently of thespecified condition. All memory alterable addressing modes may be used for the effectiveaddress. A Fast Short Jump addressing mode may also be used. The 12-bit data iszero extended to form the effective address. See Section A.9 for restrictions. The term"cc" may specify the following conditions:CC (HS)CS (LO)ECEQESGEGTLCLELSLTMINENRPLNN"cc" Mnemonic- carry clear (higher or same)- carry set (lower)- extension clear- equal- extension set- greater than or equal- greater than-limit clear- less than or equal-limit set-less than- minus- not equal- normalized-plus- not normalizedwhereIT denotes the logical complement of U,+ denotes the logical OR operator,• denotes the logical AND operator, andEe denotes the logical Exclusive OR operatorConditionC=OC=1E=OZ=1E=1NEe V=OZ+(N Ee V)=OL=OZ+(N EE> V)=1L=1N E9 V=1N=1Z=OZ+(UeE)=1N=OZ+(ITeE)=0

Jcc Jump Conditionally JccRestrictions: A Jcc instruction used within a DO loop cannot begin at the address LAwithin that DO loop.A Jcc instruction cannot be repeated using the REP Instruction.Example:JNN - (R4);jump to P:(R4) -1 if not normalizedExplanation of Example: In this example, program execution is transferred to theaddress P:(R4)-1 if the result is not normalized. Note that the contents of address registerR4 are predecremented by 1, and the resulting address is then loaded into the programcounter (PC) if the specified condition is true. If the specified condition is not true,no jump is taken, and the program counter is incremented by one.Condition Codes:15 14 13 12 11 10 9 8 7 6 5 4I LF I OM I T I" I 81 I 80 I 11 I 10 I 8 I L E I uThe condition codes are not affected by this instruction.Instruction Format:Jcc xxxeeR3 2 oN I z I vOpcode:23 16 15 8 710 0 0 0 1 1 1 ole e e e a a a alaoa a a a a a al-

Jcc Jump Conditionally JccRestrictions: A Jcc instruction used within a DO loop cannot begin at the address LAwithin that DO loop.A Jcc instruction cannot be repeated using the REP Instruction.Example:JNN - (R4);jump to P:(R4) -1 if not normalizedExplanation <strong>of</strong> Example: In this example, program execution is transferred to theaddress P:(R4)-1 if the result is not normalized. Note that the contents <strong>of</strong> address registerR4 are predecremented by 1, and the resulting address is then loaded into the programcounter (PC) if the specified condition is true. If the specified condition is not true,no jump is taken, and the program counter is incremented by one.Condition Codes:15 14 13 12 11 10 9 8 7 6 5 4I LF I OM I T I" I 81 I 80 I 11 I 10 I 8 I L E I uThe condition codes are not affected by this instruction.Instruction Format:Jcc xxxeeR3 2 oN I z I vOpcode:23 16 15 8 710 0 0 0 1 1 1 ole e e e a a a alaoa a a a a a al-

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