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- #----------------------------------------
- # Purpose - Create some $BIT variables
- # Create $K and $M variables
- # and some bit field extraction variables.
- # Creat helper variables ...
- # BIT0.. BIT31
-
- for { set x 0 } { $x < 32 } { set x [expr $x + 1]} {
- set vn [format "BIT%d" $x]
- global $vn
- set $vn [expr (1 << $x)]
- }
-
- # Create K bytes values
- # __1K ... to __2048K
- for { set x 1 } { $x < 2048 } { set x [expr $x * 2]} {
- set vn [format "__%dK" $x]
- global $vn
- set $vn [expr (1024 * $x)]
- }
-
- # Create M bytes values
- # __1M ... to __2048K
- for { set x 1 } { $x < 2048 } { set x [expr $x * 2]} {
- set vn [format "__%dM" $x]
- global $vn
- set $vn [expr (1024 * 1024 * $x)]
- }
-
- proc create_mask { MSB LSB } {
- return [expr (((1 << ($MSB - $LSB + 1))-1) << $LSB)]
- }
-
- # Cut Bits $MSB to $LSB out of this value.
- # Example: % format "0x%08x" [extract_bitfield 0x12345678 27 16]
- # Result: 0x02340000
-
- proc extract_bitfield { VALUE MSB LSB } {
- return [expr [create_mask $MSB $LSB] & $VALUE]
- }
-
-
- # Cut bits $MSB to $LSB out of this value
- # and shift (normalize) them down to bit 0.
- #
- # Example: % format "0x%08x" [normalize_bitfield 0x12345678 27 16]
- # Result: 0x00000234
- #
- proc normalize_bitfield { VALUE MSB LSB } {
- return [expr [extract_bitfield $VALUE $MSB $LSB ] >> $LSB]
- }
-
- proc show_normalize_bitfield { VALUE MSB LSB } {
- set m [create_mask $MSB $LSB]
- set mr [expr $VALUE & $m]
- set sr [expr $mr >> $LSB]
- echo [format "((0x%08x & 0x%08x) -> 0x%08x) >> %2d => (0x%x) %5d " $VALUE $m $mr $LSB $sr $sr]
- return $sr
- }
-
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