AtomSim Simulation Modes
AtomSim can be run in 2 modes, normal and interactive mode.
Normal Mode
In this mode of simulation, no debug information is printed. Optionally user can enable printing of UART traffic to
stdout using --enable-uart-dump / -u CLI option while invoking atomsim. Using --verbose / -v flag shows
additional useful information. Checkout AtomSim CLI Argument Reference for information on CLI options.
$ atomsim sw/examples/banner/banner.elf -v
___ __ _____
/ _ |/ /____ __ _ / __(_)_ _
/ __ / __/ _ \/ ' \_\ \/ / ' \
/_/ |_\__/\___/_/_/_/___/_/_/_/_/ v2.2
soctarget: hydrogensoc
Initializing ram
Initialization complete!
EBreak hit at 0x2000007c
Exiting..
Debug/Interactive Mode
Debug/Interactive mode of AtomSim presents a console interface to the user, allowing them to interact with the simulation in real-time. The console is similar to the GDB console and inherits many features from it like stepping, breakpoints etc.
To invoke AtomSim in interactive debug mode, invoke atomsim with --debug / -d flag.
___ __ _____
/ _ |/ /____ __ _ / __(_)_ _
/ __ / __/ _ \/ ' \_\ \/ / ' \
/_/ |_\__/\___/_/_/_/___/_/_/_/_/ v2.2
[ 1] PC: 0x00000000, IR: 0x00000013, _
atomsim>
As shown above, AtomSim will display the current cycle count, PC value, Instruction Register value and its disassembly
respectively. To see register file contents, users can use the info / i command in the AtomSim console.
Alternatively, If invoked with both --debug / -d and --verbose / -v CLI options, AtomSim presents a more verbose
interface with register file contents in each cycle.
___ __ ____
/ _ |/ /____ __ _ / __(_)_ _
/ __ / __/ _ \/ ' \_\ \/ / ' \
/_/ |_\__/\___/_/_/_/___/_/_/_/_/ v2.2
soctarget: hydrogensoc
Initializing ram
Initialization complete!
┌─[ 1]─────────────────────────────────────────────┐
│ PC: 0x00000000 PC_f: 0x00010000 ( +65536 ) │
│ IR: 0x00000013 _ │
└──────────────────────────────────────────────────────────┘
x0 (zero) : 0x00000000 x16 (a6) : 0x00000000
x1 (ra) : 0x00000000 x17 (a7) : 0x00000000
x2 (sp) : 0x00000000 x18 (s2) : 0x00000000
x3 (gp) : 0x00000000 x19 (s3) : 0x00000000
x4 (tp) : 0x00000000 x20 (s4) : 0x00000000
x5 (t0) : 0x00000000 x21 (s5) : 0x00000000
x6 (t1) : 0x00000000 x22 (s6) : 0x00000000
x7 (t2) : 0x00000000 x23 (s7) : 0x00000000
x8 (s0/fp): 0x00000000 x24 (s8) : 0x00000000
x9 (s1) : 0x00000000 x25 (s9) : 0x00000000
x10 (a0) : 0x00000000 x26 (s10) : 0x00000000
x11 (a1) : 0x00000000 x27 (s11) : 0x00000000
x12 (a2) : 0x00000000 x28 (t3) : 0x00000000
x13 (a3) : 0x00000000 x29 (t4) : 0x00000000
x14 (a4) : 0x00000000 x30 (t5) : 0x00000000
x15 (a5) : 0x00000000 x31 (t6) : 0x00000000
atomsim>
Try the help command to checkout the commands available in AtomSim console.
Tips for using AtomSim in interactive mode
If simulation is run in normal mode, pressing ctrl + c returns AtomSim to interactive mode and pressing ctrl + c in interactive mode terminates the simulation.
AtomSim has shorter aliases for most of the command names which can be seen in command help.
AtomSim console is based on the linux readline library which allows user to press up / down arrow keys to cycle between previously entered commands.
If user presses enter without entering a command, AtomSim executes the last executed command.
When entering numeric values in console such as addresses, users can specify in decimal, hexadecimal (by prefixing the value with 0x), or binary (by prefixng the value with 0b).
Register names can be specified as physical register names (x0, x1, x2 …) or their ABI names (zero, ra, sp…)
Some of effects of CLI arguments can be overridden in the AtomSim console, like enabling/disabling trace, verbosity etc.
Lastly, refer to the
helpcommand to find most up-to-date information related to the AtomSim console.