SVE Instruction List by Dougall Johnson
RSHRNB: Rounding shift right narrow by immediate (bottom)
RSHRNB Zd.B, Zn.H, #const (SVE2 (SME
svint8_t svrshrnb[_n_s16](svint16_t op1, uint64_t imm2)
svuint8_t svrshrnb[_n_u16](svuint16_t op1, uint64_t imm2)
128-bit SVE
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For each 16-bit integer set the even 8-bit elements of (2) to ( (1) + ( 1 << ( const − 1 ) ) >> const, and zero odd elements. This is the same as a regular shift, but with result incremented if the most-significant bit that was shifted out was set. The shift amount is limited to 1 ≤ const ≤ 8.
256-bit SVE
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For each 16-bit integer set the even 8-bit elements of (2) to ( (1) + ( 1 << ( const − 1 ) ) >> const, and zero odd elements. This is the same as a regular shift, but with result incremented if the most-significant bit that was shifted out was set. The shift amount is limited to 1 ≤ const ≤ 8.
512-bit SVE
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For each 16-bit integer set the even 8-bit elements of (2) to ( (1) + ( 1 << ( const − 1 ) ) >> const, and zero odd elements. This is the same as a regular shift, but with result incremented if the most-significant bit that was shifted out was set. The shift amount is limited to 1 ≤ const ≤ 8.
Larger sizes
1024-bit SVE
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For each 16-bit integer set the even 8-bit elements of (2) to ( (1) + ( 1 << ( const − 1 ) ) >> const, and zero odd elements. This is the same as a regular shift, but with result incremented if the most-significant bit that was shifted out was set. The shift amount is limited to 1 ≤ const ≤ 8.
2048-bit SVE
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For each 16-bit integer set the even 8-bit elements of (2) to ( (1) + ( 1 << ( const − 1 ) ) >> const, and zero odd elements. This is the same as a regular shift, but with result incremented if the most-significant bit that was shifted out was set. The shift amount is limited to 1 ≤ const ≤ 8.
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Inspired by and based on the x86/x64 SIMD Instruction List by Daytime.