maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

Enhanced the existing ARMExpandImm() and ThumbExpandImm() functions which expand 

an imm12 into imm32 for ARM or Thumb so that they now handle carry_in/carry_out.
Funnel ARMExpandImm()/ThumbExpandImm() to the enhanced ARMExpandImm_C()/ThumbExpandImm_C()
functions.

llvm-svn: 125508
This commit is contained in:
Johnny Chen 2011-02-14 19:08:41 +00:00
parent f0619868ae
commit e2b86a3a83
1 changed files with 66 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

101
lldb/source/Plugins/Process/Utility/ARMUtils.h
View File

@ -32,47 +32,78 @@ static uint32_t ror(uint32_t val, uint32_t N, uint32_t shift)
return (val >> m) | (val << (N - m));
}
// (imm32, carry_out) = ARMExpandImm_C(imm12, carry_in)
static inline uint32_t ARMExpandImm_C(uint32_t val, uint32_t carry_in, uint32_t &carry_out)
{
uint32_t imm32; // the expanded result
uint32_t imm = bits(val, 7, 0); // immediate value
uint32_t amt = 2 * bits(val, 11, 8); // rotate amount
if (amt == 0)
{
imm32 = imm;
carry_out = carry_in;
}
else
{
imm32 = ror(imm, 32, amt);
carry_out = Bit32(imm32, 31);
}
return imm32;
}
static inline uint32_t ARMExpandImm(uint32_t val)
{
uint32_t imm = bits(val, 7, 0); // immediate value
uint32_t rot = 2 * bits(val, 11, 8); // rotate amount
return (imm >> rot) | (imm << (32 - rot));
// 'carry_in' argument to following function call does not affect the imm32 result.
uint32_t carry_in = 0;
uint32_t carry_out;
return ARMExpandImm_C(val, carry_in, carry_out);
}
// (imm32, carry_out) = ThumbExpandImm_C(imm12, carry_in)
static inline uint32_t ThumbExpandImm_C(uint32_t val, uint32_t carry_in, uint32_t &carry_out)
{
uint32_t imm32;
const uint32_t i = bit(val, 26);
const uint32_t imm3 = bits(val, 14, 12);
const uint32_t abcdefgh = bits(val, 7, 0);
const uint32_t imm12 = i << 11 | imm3 << 8 | abcdefgh;
if (bits(imm12, 11, 10) == 0)
{
switch (bits(imm12, 8, 9)) {
case 0:
imm32 = abcdefgh;
break;
case 1:
imm32 = abcdefgh << 16 | abcdefgh;
break;
case 2:
imm32 = abcdefgh << 24 | abcdefgh << 8;
break;
case 3:
imm32 = abcdefgh << 24 | abcdefgh << 16 | abcdefgh << 8 | abcdefgh;
break;
}
carry_out = carry_in;
}
else
{
const uint32_t unrotated_value = 0x80 | bits(imm12, 6, 0);
imm32 = ror(unrotated_value, 32, bits(imm12, 11, 7));
carry_out = Bit32(imm32, 31);
}
return imm32;
}
static inline uint32_t ThumbExpandImm(uint32_t val)
{
uint32_t imm32 = 0;
const uint32_t i = bit(val, 26);
const uint32_t imm3 = bits(val, 14, 12);
const uint32_t abcdefgh = bits(val, 7, 0);
const uint32_t imm12 = i << 11 | imm3 << 8 | abcdefgh;
if (bits(imm12, 10, 11) == 0)
{
switch (bits(imm12, 8, 9)) {
case 0:
imm32 = abcdefgh;
break;
case 1:
imm32 = abcdefgh << 16 | abcdefgh;
break;
case 2:
imm32 = abcdefgh << 24 | abcdefgh << 8;
break;
case 3:
imm32 = abcdefgh << 24 | abcdefgh << 16 | abcdefgh << 8 | abcdefgh;
break;
}
}
else
{
const uint32_t unrotated_value = 0x80 | bits(imm12, 0, 6);
imm32 = ror(unrotated_value, 32, bits(imm12, 7, 11));
}
return imm32;
// 'carry_in' argument to following function call does not affect the imm32 result.
uint32_t carry_in = 0;
uint32_t carry_out;
return ThumbExpandImm_C(val, carry_in, carry_out);
}
// imm32 = ZeroExtend(i:imm3:imm8, 32)