From: Rémi Denis-Courmont <r...@remlab.net>
On most cases, the vector type (VTYPE) for the RISC-V Vector extension
is supplied as an immediate value, with either of the VSETVLI or
VSETIVLI instructions. There is however a third instruction VSETVL
which takes the vector type from a general purpose register. That is so
the type can be selected at run-time.
This introduces a macro to load a (valid) vector type into a register.
The syntax follows that of VSETVLI and VSETIVLI, with element size,
group multiplier, then tail and mask policies.
---
libavutil/riscv/asm.S | 75 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/libavutil/riscv/asm.S b/libavutil/riscv/asm.S
index de5e1ad0a6..f8c9f6749b 100644
--- a/libavutil/riscv/asm.S
+++ b/libavutil/riscv/asm.S
@@ -94,3 +94,78 @@
shnadd 3, \rd, \rs1, \rs2
.endm
#endif
+
+ /* Convenience macro to load a Vector type (vtype) as immediate */
+ .macro lvtypei rd, e, m=m1, tp=tu, mp=mu
+
+ .ifc \e,e8
+ .equ ei, 0
+ .else
+ .ifc \e,e16
+ .equ ei, 8
+ .else
+ .ifc \e,e32
+ .equ ei, 16
+ .else
+ .ifc \e,e64
+ .equ ei, 24
+ .else
+ .error "Unknown element type"
+ .endif
+ .endif
+ .endif
+ .endif
+
+ .ifc \m,m1
+ .equ mi, 0
+ .else
+ .ifc \m,m2
+ .equ mi, 1
+ .else
+ .ifc \m,m4
+ .equ mi, 2
+ .else
+ .ifc \m,m8
+ .equ mi, 3
+ .else
+ .ifc \m,mf8
+ .equ mi, 5
+ .else
+ .ifc \m,mf4
+ .equ mi, 6
+ .else
+ .ifc \m,mf2
+ .equ mi, 7
+ .else
+ .error "Unknown multiplier"
+ .equ mi, 3
+ .endif
+ .endif
+ .endif
+ .endif
+ .endif
+ .endif
+ .endif
+
+ .ifc \tp,tu
+ .equ tpi, 0
+ .else
+ .ifc \tp,ta
+ .equ tpi, 64
+ .else
+ .error "Unknown tail policy"
+ .endif
+ .endif
+
+ .ifc \mp,mu
+ .equ mpi, 0
+ .else
+ .ifc \mp,ma
+ .equ mpi, 128
+ .else
+ .error "Unknown mask policy"
+ .endif
+ .endif
+
+ li \rd, (ei | mi | tpi | mpi)
+ .endm
--
2.37.2
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
To unsubscribe, visit link above, or email
ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
