Sorry about the mistake made in previous letter.
hi, all.
I found there are some switchs like switch cases (C/C++) in the files
"decode.cc" or "arm.isa"
here's the code below:
-----------------------------------------------------------------
StaticInstPtr ArmISA::Decoder::decodeInst(ArmISA::ExtMachInst machInst){
using namespace ArmISAInst;
switch (THUMB) {
case 0x0:
switch (AARCH64) {
case 0x0:
switch (COND_CODE) {
case 0xf:
// ArmUnconditional::armUnconditional(([], {})) {
...
break;
default: switch (ENCODING) {
case 0x0:
switch (SEVEN_AND_FOUR) {
...
...
...
-----------------------------------------------------------------
I'd like know what's the switch criterion?
Such as "THUMB" , "AARCH64" , "COND_CODE" , "ENCODING" , "SEVEN_AND_FOUR"
...etc.
Are they defined in the file "arch/arm/types.hh" ? But it seem to be
different?
here's the code below:
-----------------------------------------------------------------
BitUnion64(ExtMachInst)
// ITSTATE bits
Bitfield<55, 48> itstate;
Bitfield<55, 52> itstateCond;
Bitfield<51, 48> itstateMask;
// FPSCR fields
Bitfield<41, 40> fpscrStride;
Bitfield<39, 37> fpscrLen;
// Bitfields to select mode.
Bitfield<36> thumb; // here it's what I mentioned
Bitfield<35> bigThumb; // here it's what I mentioned
Bitfield<34> aarch64; // here it's what I mentioned
// Made up bitfields that make life easier.
Bitfield<33> sevenAndFour; // here it's what I mentioned
Bitfield<32> isMisc; // here it's what I mentioned
uint32_t instBits;
// All the different types of opcode fields.
Bitfield<27, 25> encoding;
...
...
...
-----------------------------------------------------------------
And in the file "arm.isa" there's a paragraph
'''
// The actual ARM ISA decoder
// --------------------------
// The following instructions are specified in the ARM ISA
// Specification. Decoding closely follows the style specified
// in the ARM ISA specification document starting with Table B.1 or 3-1
'''
What's Table B.1 or 3-1? Where's it?
I've read "ARM Architecture Reference Manual", but I did not find it.
Thanks!
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