Cmep basics

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Revision as of 21:51, 6 January 2019 by Yifan Lu (talk | contribs) (2 revisions imported)
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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.

$cfg

0xF00004AA

$ccfg

0x5B105B08

$rcfg

0x01000100

$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