Improve immediate types of instructions

[nazar-pc]

Extracted from my local branch, should be much more fitting.

There are also some other minor changes included.

[Copilot]

Pull request overview

This pull request improves the type safety and clarity of RISC-V instruction immediate values by using more appropriate integer types. The PR changes I-type and S-type immediate fields from i32 to i16 (which properly represents 12-bit signed values), and shift amount fields from u32 to u8 (which properly represents 6-bit unsigned values). Additionally, it improves code clarity by using i64::from() instead of as i64 casts and refactors test utilities for better genericity.

Changes:

• Changed immediate value types from i32 to i16 for I-type and S-type instructions (12-bit signed immediates)
• Changed shift amount types from u32 to u8 for shift instructions (6-bit and 5-bit unsigned values)
• Replaced as i64 casts with i64::from() for clearer type conversions in the interpreter
• Consolidated test utility functions for improved code reuse
• Added /build.rs to package include lists for proper distribution

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/execution/ab-riscv-primitives/src/instruction/rv64.rs	Changed immediate types from i32 to i16 and shift amounts from u32 to u8 in instruction enum and decoder
crates/execution/ab-riscv-primitives/Cargo.toml	Reordered include list to put /src before /build.rs
crates/execution/ab-riscv-interpreter/src/rv64/test_utils.rs	Refactored test utilities to use generic Into trait for better code reuse
crates/execution/ab-riscv-interpreter/src/rv64/m/tests.rs	Updated test calls to use renamed function
crates/execution/ab-riscv-interpreter/src/rv64/b/zbs/tests.rs	Updated test calls to use renamed function
crates/execution/ab-riscv-interpreter/src/rv64/b/zbc/tests.rs	Updated test calls to use renamed function
crates/execution/ab-riscv-interpreter/src/rv64/b/zbb/tests.rs	Updated test calls to use renamed function
crates/execution/ab-riscv-interpreter/src/rv64/b/zba/tests.rs	Updated test calls to use renamed function
crates/execution/ab-riscv-interpreter/src/rv64.rs	Updated interpreter to use i64::from() instead of as casts when converting immediates
crates/execution/ab-riscv-interpreter/Cargo.toml	Added /build.rs to include list
crates/execution/ab-riscv-benchmarks/Cargo.toml	Added /build.rs to include list

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