ptx-90-parser 0.4.4

Parse NVIDIA PTX 9.0 assembly into a structured AST and explore modules via a CLI.
Documentation 
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### Description

Find the bit position of the most significant non-sign bit in a and place the result in
d. Operand a has the instruction type, and destination d has type .u32. For unsigned
integers, bfind returns the bit position of the most significant 1. For signed integers,
bfind returns the bit position of the most significant 0 for negative inputs and the most
significant 1 for non-negative inputs.
If .shiftamt is specified, bfind returns the shift amount needed to left-shift the found bit
into the most-significant bit position.
bfind returns 0xffffffff if no non-sign bit is found.

### Syntax

```
bfind.type           d, a;
bfind.shiftamt.type  d, a;

.type = { .u32, .u64,
          .s32, .s64 };
```

### Semantics

```
msb = (.type==.u32 || .type==.s32) ? 31 : 63;
// negate negative signed inputs
if ( (.type==.s32 || .type==.s64) && (a & (1<<msb)) ) {
    a = ~a;
}
.u32  d = 0xffffffff;
for (.s32 i=msb; i>=0; i--) {
    if (a & (1<<i))  { d = i; break; }
}
if (.shiftamt && d != 0xffffffff)  { d = msb - d; }
```

### Examples

```
bfind.u32  d, a;
bfind.shiftamt.s64  cnt, X;  // cnt is .u32
```