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 ffa0bd9068..6ca74f263a 100644 --- a/libavutil/riscv/asm.S +++ b/libavutil/riscv/asm.S @@ -92,3 +92,78 @@ 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".