sclamp.c File Reference

Implements the OP_SCLAMP opcode for signed N-bit two's-complement wrapping. More...

Go to the source code of this file.

Functions
	if (bits<=0)
	if (bits >=64)
	if (wrapped &sign_bit)
	push_value (vm, make_int(out))
	free_value (v)

Variables
case	OP_SCLAMP
int	bits = inst.operand
int64_t	vi = (v.type == VAL_INT) ? v.i : 0
int64_t	out = 0
	else
uint64_t	wrapped = ((uint64_t)vi) & mask
	break

Detailed Description

Implements the OP_SCLAMP opcode for signed N-bit two's-complement wrapping.

This VM opcode wraps an integer into the signed N-bit range using two's complement semantics. It first masks to N bits and then sign-extends if the sign bit is set, yielding a value in the range [-2^(N-1) .. 2^(N-1)-1]. N is provided by the instruction operand.

Stack contract:

• Pops: value (int)
• Pushes: value (int)

Definition in file sclamp.c.

Function Documentation

free_value()

free_value

(

v

)

if() [1/3]

if

(

bits >=

64

)

Definition at line 39 of file sclamp.c.

if() [2/3]

if

(

bits<=

0

)

Definition at line 34 of file sclamp.c.

if() [3/3]

if

(

wrapped &

sign_bit

)

Definition at line 44 of file sclamp.c.

push_value()

push_value	(	vm	,
		make_int(out)	)

Variable Documentation

bits

int bits = inst.operand

Definition at line 30 of file sclamp.c.

break

break

Definition at line 55 of file sclamp.c.

else

else

Initial value:

{
uint64_t mask = (bits >= 64) ? UINT64_MAX : ((1ULL << bits) - 1ULL)

Definition at line 36 of file sclamp.c.

OP_SCLAMP

case OP_SCLAMP

Definition at line 24 of file sclamp.c.

out

int64_t out = 0

Definition at line 33 of file sclamp.c.

vi

int64_t vi = (v.type == VAL_INT) ? v.i : 0

Definition at line 31 of file sclamp.c.

wrapped

uint64_t wrapped = ((uint64_t)vi) & mask

Definition at line 38 of file sclamp.c.