diff options
Diffstat (limited to 'tcg/README')
| -rw-r--r-- | tcg/README | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/tcg/README b/tcg/README index ae31388c59..065d9c2966 100644 --- a/tcg/README +++ b/tcg/README @@ -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 |