Epson S5U1C63000A - Manual (Page 194)

CHAPTER 8: DEBUGGER
180 EPSON S5U1C63000A MANUAL
(S1C63 FAMILY ASSEMBLER PACKAGE)
s
(step)
Function
This command single-steps the target program from the current PC position by executing one instruc-
tion at a time.
Format
>s [<step>]
↵
(direct input mode)
<step>: Number of steps to be executed; decimal (default is 1)
Condition: 0
≤
step
≤
65,535
Operation
(1) Step execution
If the <step> is omitted, only the program step at the address indicated by the PC is executed, other-
wise the specified number of program steps is executed from the address indicated by the PC.
>s
↵
...Executes one step at the current PC address.
>s 20
↵
...Executes 20 steps from the current PC address.
The program execution is suspended by the following cause even before the specified number of steps
is completed.
• The [Key Break] button is clicked or the [Esc] key is pressed
• A map break, etc. occurs
After each step is completed, the register contents in the [Register] window are updated. If the
[Register] window is closed, the register contents are displayed in the [Command] window same as
executing the rd command.
When program execution is completed by stepping through instructions, the system stands by
waiting for command input. If you hit the [Enter] key here, the system single-steps the program in the
same way again.
(2) HALT and SLEEP states and interrupts
When the halt or slp instruction is executed, the CPU is placed in standby mode. An interrupt is
required to clear this mode. The debugger has a mode to enable or disable an external interrupt for
use in a single-step operation.
External interrupt
halt and slp instructions
Enable mode
Interrupt is processed.
Executed as the halt instruction.
Processing is continued by an
external interrupt or clicking on
the [Key Break] button.
Disable mode
Interrupt is not processed.
The halt and slp instructions are
replaced with a nop instruction as
the instruction is executed.
In the initial settings, the debugger is set to the interrupt disable mode.
The interrupt enable mode can also be set by using the md command.
(3) Execution cycle counter
The execution cycle counter displayed in the [Register] window indicates the number of cycles
executed or the execution time of the target program.
In the initial debugger settings, the execution cycle counter is set to hold mode so that execution time
is added up until the CPU is reset. If this mode is changed to reset mode by the md command, the
execution cycle counter is cleared to 0 each time the s command is executed. The counter is also reset
simultaneously when execution is restarted by hitting the [Enter] key.