trunc_f64_s: Wasm text instruction
The trunc_f64_s instruction removes the fractional part of an f64 value and outputs it as a signed integer.
This is a separate instruction, trunc, which removes the fractional part of a float and outputs a float.
There are also other truncate integer conversion instructions:
Try it
(module
(import "console" "log" (func $log (param i32)))
(func $main
f64.const 2300044.4 ;; load a number onto the stack
i32.trunc_f64_s ;; discard decimal part and return signed integer
call $log ;; log the result
)
(start $main)
)
const url = "{%wasm-url%}";
await WebAssembly.instantiateStreaming(fetch(url), { console });
Syntax
value_type.trunc_f64_s
value_type-
The type of value the instruction is being run on. The following types support
trunc_f64_s:i32i64
trunc_f64_s-
The
trunc_f64_sinstruction. Must always be included after thevalue_typeand a period (.).
Type
[input] -> [output]
Binary encoding
| Instruction | Binary format | Example text => binary |
|---|---|---|
i32.trunc_f64_s |
0xaa |
i32.trunc_f64_s => 0xaa |
i64.trunc_f64_s |
0xb0 |
i64.trunc_f64_s => 0xb0 |