HP 113394 User Guide - Page 125

Section 9 Branching and Looping Although the instructions in a program normally are executed in order of their program line numbers, in some situations it is desirable to have program execution transfer or "branch" to a program line that is not the next line in program memory. Branching also makes it possible to automatically execute portions of a program more than once - a process called "looping." Simple Branching The i (go to) instruction is used in a program to transfer execution to any program line. The program line desired is specified by keying its three-digit line number into the program line containing the i instruction. When the i instruction is executed, program execution branches or "goes to" the program line specified and then continues sequentially as usual. You have already seen a common use of branching: the gi000 instruction (that is stored in program memory after the program you key in) transfers execution to program line 000. A i instruction can be used to branch not only backward in program memory - as in the case of gi000 and as illustrated above - but also forward in program memory. Backward branching is typically done to create loops (as described next); forward branching is typically done in conjunction with a go or gm instruction for conditional branching (as described afterward). 125 File name: hp 12c pt_user's guide_English_HDPMF123E27 Page: 125 of 275 Printed Date: 2005/8/1 Dimension: 14.8 cm x 21 cm