Cmep basics

Calling convention

• $1 = arg0
• $2 = arg1
• $3 = arg2
• $4 = arg3

Unmodified by callee: $5, $6, $7, $8

Clobbered by callee: $9, $10, $11, $12

Configuration

Note: This is dumped with a sm exploit. Some options are read/write so it might differ.

$opt

0x03FD0201

This register is read-only.

• CBS = 00: coprocessor data bus width 32-bit
• DBS = 00: DSP data bus width 32-bit
• 0
• HWE = 0: hardware engine off
• DIV = 1: 32-bit divide instruction on
• MUL = 1: multiply instruction on
• BIT = 1: bit manipulation instruction on
• SAT = 1: saturation instruction on
• CLP = 1: clip instruction on
• MIN = 1: min/max instruction on
• AVE = 1: average instruction on
• ABS = 1: abs instruction on
• 0
• LDZ = 1: leading zero instruction on
• BIS = 00: bus interface width is 32-bit
• LBS = 00: local bus interface width is 32-bit
• 0
• TCN = 010: 2 timer/counter channels
• 0
• VL64 = 0: 64-bit VLIW off
• VL32 = 0: 32-bit VLIW off
• COP = 0: coprocessor off
• 0
• DSP = 0: DSP off
• UCI = 0: UCI off
• DBG = 1: DBG on