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4.6.2.26 JGE
JGE Jump if greater or equal (signed)
JGE label
Syntax
Operation If (N .xor. V) = 0: PC + (2 × Offset) → PC
If (N .xor. V) = 1: execute following instruction
Description
The negative bit N and the overflow bit V in the SR are tested. If both bits are set or both
are reset, the signed 10-bit word offset contained in the instruction is multiplied by two,
sign extended, and added to the 20-bit PC. This means a jump in the range -511 to +512
words relative to the PC in full Memory range. If only one bit is set, the instruction after
the jump is executed.
JGE is used for the comparison of signed operands: also for incorrect results due to
overflow, the decision made by the JGE instruction is correct.
Note: JGE emulates the nonimplemented JP (jump if positive) instruction if used after the
instructions AND, BIT, RRA, SXTX, and TST. These instructions clear the V bit.
Status Bits Status bits are not affected.
Mode Bits OSCOFF, CPUOFF, and GIE are not affected.
Example If byte EDE (lower 64KB) contains positive data, go to Label1. Software can run in the
full memory range.
TST.B &EDE ; Is EDE positive? V <- 0
JGE Label1 ; Yes, JGE emulates JP
... ; No, 80h <= EDE <= FFh
Example If the content of R6 is greater than or equal to the memory pointed to by R7, the program
continues a Label5. Signed data. Data and program in full memory range.
CMP @R7,R6 ; Is R6 >= @R7?
JGE Label5 ; Yes, go to Label5
... ; No, continue here
Example If R5 ≥ 12345h (signed operands), the program continues at Label2. Program in full
memory range.
CMPA #12345h,R5 ; Is R5 >= 12345h?
JGE Label2 ; Yes, 12344h < R5 <= 7FFFFh
... ; No, 80000h <= R5 < 12345h
189
SLAU144J–December 2004–Revised July 2013 CPUX
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