TC1796
System Units (Vol. 1 of 2)
Peripheral Control Processor (PCP)
User’s Manual 11-98 V2.0, 2007-07
PCP, V2.0
11.11.28 PRI, Prioritize
This section describes the PRI instruction of the PCP.
PRId Syntax PRI Rb, Ra, cc_A
Description If condition CONDCA is true, then find the bit position of the
most significant 1 in register Ra and put the number into
register Rb. The bit location, 31..0, is encoded as a 5-bit
number stored in Rb[4:0]. If the contents of Ra is zero, bit
Rb[5] is set, while all other bits in Rb are cleared. If CONDCA
is false, no operation is performed.
Operation if (CONDCA = False) then
NOP
else
if (R[a] = 0) then
R[b] = 0x20
else
R[b] = bit_pos(most_significant_1(R[a]))
Flags N, Z
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