Commit 7ec8bab3 authored by Richard Henderson's avatar Richard Henderson
Browse files

tcg: Add field extraction primitives 



Adds tcg_gen_extract_* and tcg_gen_sextract_* for extraction of
fixed position bitfields, much like we already have for deposit.

Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent 41a0e547

tcg/README

+18 −2
Original line number Diff line number Diff line
@@ -314,11 +314,27 @@ The bitfield is described by POS/LEN, which are immediate values: 
  LEN - the length of the bitfield

  POS - the position of the first bit, counting from the LSB



For example, pos=8, len=4 indicates a 4-bit field at bit 8.

This operation would be equivalent to

For example, "deposit_i32 dest, t1, t2, 8, 4" indicates a 4-bit field

at bit 8.  This operation would be equivalent to



  dest = (t1 & ~0x0f00) | ((t2 << 8) & 0x0f00)



* extract_i32/i64 dest, t1, pos, len

* sextract_i32/i64 dest, t1, pos, len



Extract a bitfield from T1, placing the result in DEST.

The bitfield is described by POS/LEN, which are immediate values,

as above for deposit.  For extract_*, the result will be extended

to the left with zeros; for sextract_*, the result will be extended

to the left with copies of the bitfield sign bit at pos + len - 1.



For example, "sextract_i32 dest, t1, 8, 4" indicates a 4-bit field

at bit 8.  This operation would be equivalent to



  dest = (t1 << 20) >> 28



(using an arithmetic right shift).



* extrl_i64_i32 t0, t1



For 64-bit hosts only, extract the low 32-bits of input T1 and place it

tcg/aarch64/tcg-target.h

+4 −0
Original line number Diff line number Diff line
@@ -63,6 +63,8 @@ typedef enum { 
#define TCG_TARGET_HAS_nand_i32         0

#define TCG_TARGET_HAS_nor_i32          0

#define TCG_TARGET_HAS_deposit_i32      1

#define TCG_TARGET_HAS_extract_i32      0

#define TCG_TARGET_HAS_sextract_i32     0

#define TCG_TARGET_HAS_movcond_i32      1

#define TCG_TARGET_HAS_add2_i32         1

#define TCG_TARGET_HAS_sub2_i32         1
@@ -93,6 +95,8 @@ typedef enum { 
#define TCG_TARGET_HAS_nand_i64         0

#define TCG_TARGET_HAS_nor_i64          0

#define TCG_TARGET_HAS_deposit_i64      1

#define TCG_TARGET_HAS_extract_i64      0

#define TCG_TARGET_HAS_sextract_i64     0

#define TCG_TARGET_HAS_movcond_i64      1

#define TCG_TARGET_HAS_add2_i64         1

#define TCG_TARGET_HAS_sub2_i64         1

tcg/arm/tcg-target.h

+2 −0
Original line number Diff line number Diff line
@@ -80,6 +80,8 @@ extern bool use_idiv_instructions; 
#define TCG_TARGET_HAS_nand_i32         0

#define TCG_TARGET_HAS_nor_i32          0

#define TCG_TARGET_HAS_deposit_i32      1

#define TCG_TARGET_HAS_extract_i32      0

#define TCG_TARGET_HAS_sextract_i32     0

#define TCG_TARGET_HAS_movcond_i32      1

#define TCG_TARGET_HAS_mulu2_i32        1

#define TCG_TARGET_HAS_muls2_i32        1

tcg/i386/tcg-target.h

+4 −0
Original line number Diff line number Diff line
@@ -94,6 +94,8 @@ extern bool have_bmi1; 
#define TCG_TARGET_HAS_nand_i32         0

#define TCG_TARGET_HAS_nor_i32          0

#define TCG_TARGET_HAS_deposit_i32      1

#define TCG_TARGET_HAS_extract_i32      0

#define TCG_TARGET_HAS_sextract_i32     0

#define TCG_TARGET_HAS_movcond_i32      1

#define TCG_TARGET_HAS_add2_i32         1

#define TCG_TARGET_HAS_sub2_i32         1
@@ -124,6 +126,8 @@ extern bool have_bmi1; 
#define TCG_TARGET_HAS_nand_i64         0

#define TCG_TARGET_HAS_nor_i64          0

#define TCG_TARGET_HAS_deposit_i64      1

#define TCG_TARGET_HAS_extract_i64      0

#define TCG_TARGET_HAS_sextract_i64     0

#define TCG_TARGET_HAS_movcond_i64      1

#define TCG_TARGET_HAS_add2_i64         1

#define TCG_TARGET_HAS_sub2_i64         1

tcg/ia64/tcg-target.h

+4 −0
Original line number Diff line number Diff line
@@ -149,6 +149,10 @@ typedef enum { 
#define TCG_TARGET_HAS_movcond_i64      1

#define TCG_TARGET_HAS_deposit_i32      1

#define TCG_TARGET_HAS_deposit_i64      1

#define TCG_TARGET_HAS_extract_i32      0

#define TCG_TARGET_HAS_extract_i64      0

#define TCG_TARGET_HAS_sextract_i32     0

#define TCG_TARGET_HAS_sextract_i64     0

#define TCG_TARGET_HAS_add2_i32         0

#define TCG_TARGET_HAS_add2_i64         0

#define TCG_TARGET_HAS_sub2_i32         0