diff options
| author | Hau Hsu <hau.hsu@sifive.com> | 2024-08-06 11:56:18 +0800 |
|---|---|---|
| committer | Nelson Chu <nelson@rivosinc.com> | 2024-08-06 16:07:27 +0800 |
| commit | 87e720ad359ece678b37b036a61e0adcc60304f4 (patch) | |
| tree | 4183cbd474f45cb16b1e88a01e0512bf30d5f36f /gas/testsuite | |
| parent | 2f1739a348c59e8b095805d3eb6200ffd04be1dc (diff) | |
| download | fsf-binutils-gdb-87e720ad359ece678b37b036a61e0adcc60304f4.zip fsf-binutils-gdb-87e720ad359ece678b37b036a61e0adcc60304f4.tar.gz fsf-binutils-gdb-87e720ad359ece678b37b036a61e0adcc60304f4.tar.bz2 | |
RISC-V: map zext.h to pack/packw if Zbkb is enabled
The `zext.h` is zero-extend halfword instruction that belongs to Zbb.
Currently `zext.h` falls back to 2 shifts if Zbb is not enabled. However, the
encoding and operation is a special case of `pack/packw rd, rs1, rs2`, which
belongs to Zbkb. The instructions pack the low halves of rs1 and rs2 into rd.
When rs2 is zero (x0), they behave like zero-extend instruction, and the
encoding are exactly the same as zext.h.
Thus we can map `zext.h` to `pack` or `packw` (rv64) if Zbkb is enabled,
instead of 2 shifts. This reduces one instruction.
This patch does this by making `zext.h` also available for Zbkb.
opcodes/
* riscv-opc.c (riscv_opcodes): Update `zext.h` entries to use
`ZBB_OR_ZBKB` instruction class.
gas/
* testsuite/gas/riscv/zext-to-pack.s: Add test for mapping zext to
pack/packw encoding.
* testsuite/gas/riscv/zext-to-pack-encoding.d: Likewise.
* testsuite/gas/riscv/zext-to-packw-encoding.d: Likewise.
Diffstat (limited to 'gas/testsuite')
| -rw-r--r-- | gas/testsuite/gas/riscv/zext-to-pack-encoding.d | 11 | ||||
| -rw-r--r-- | gas/testsuite/gas/riscv/zext-to-pack.s | 2 | ||||
| -rw-r--r-- | gas/testsuite/gas/riscv/zext-to-packw-encoding.d | 11 |
3 files changed, 24 insertions, 0 deletions
diff --git a/gas/testsuite/gas/riscv/zext-to-pack-encoding.d b/gas/testsuite/gas/riscv/zext-to-pack-encoding.d new file mode 100644 index 0000000..86fcbce --- /dev/null +++ b/gas/testsuite/gas/riscv/zext-to-pack-encoding.d @@ -0,0 +1,11 @@ +#as: -march=rv32i_zbkb +#source: zext-to-pack.s +#objdump: -d + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+000 <target>: +[ ]+[0-9a-f]+:[ ]+08054533[ ]+zext.h[ ]+a0,a0 diff --git a/gas/testsuite/gas/riscv/zext-to-pack.s b/gas/testsuite/gas/riscv/zext-to-pack.s new file mode 100644 index 0000000..bb2be3d --- /dev/null +++ b/gas/testsuite/gas/riscv/zext-to-pack.s @@ -0,0 +1,2 @@ +target: + zext.h a0, a0 diff --git a/gas/testsuite/gas/riscv/zext-to-packw-encoding.d b/gas/testsuite/gas/riscv/zext-to-packw-encoding.d new file mode 100644 index 0000000..04e21e7 --- /dev/null +++ b/gas/testsuite/gas/riscv/zext-to-packw-encoding.d @@ -0,0 +1,11 @@ +#as: -march=rv64i_zbkb +#source: zext-to-pack.s +#objdump: -d + +.*:[ ]+file format .* + + +Disassembly of section .text: + +0+000 <target>: +[ ]+[0-9a-f]+:[ ]+0805453b[ ]+zext.h[ ]+a0,a0 |