User`s guide

Chapter 7: Debugging Machine Language Code

the speciﬁed conditions are met, the command list is executed. If one of the

commands in the list is stop (with no operands), then the process stops when

the command list is executed.

wheni if expression {command-list}

Evaluates the expression before executing each machine

instruction. If the expression is true, executes the command

list.

wheni at address if expression {command-list}

Evaluates the expression at the given address. If the

expression is true, executes the command list.

wheni in procedure if expression {command-list}

Evaluates the expression in the given procedure. If the

expression is true, executes the command list.

wheni variable at address if expression {command-list}

Tests both conditions at the given address. If the conditions

are true, executes the command list. (For machine-level

debugging.)

If the expression is of type pointer, look at the data pointed

to and watch until it changes. If the expression is not of type

pointer, look at the 32 bits at that address (assume the

expression evaluates to an address).

wheni variable in procedure if expression {command-list}

Tests both conditions at every machine instruction within a

given procedure. If they are true, executes the command list.

See also “Linking With DSOs” on page 90 for a description on using the

wheni in and wheni at commands with DSOs.

Stepping Through Machine Code

The stepi and nexti commands allow you to step through machine code in

much the same way as you can with the step and next commands while

debugging source code. The step and next commands step in units of

machine instructions instead of in lines of code.