TC1796
System Units (Vol. 1 of 2)
Peripheral Control Processor (PCP)
User’s Manual
11-84
V2.0, 2007-07
PCP, V2.0
11.11.10 COMP, 32-Bit Compare
This section describes the COMP instructions of the PCP.
COMP
Syntax
COMP Rb, Ra, cc_A
Description
If the condition CONDCA is true, then subtract the contents
of register Ra from the contents of register Rb; set the flags
in register R7 according to the result of the subtraction;
discard the subtraction result. If CONDCA is false, no
operation is performed.
Operation
if (CONDCA = True) then R7_FLAGS = Flags(R[b] - R[a])
Flags
N, Z, V, C
COMP.I
Syntax
COMP.I Ra, #imm6
Description
Subtract the sign-extended immediate value imm6 from the
contents of register Ra; set the flags in register R7 according
to the result of the subtraction; discard the subtraction result.
Operation
R7_FLAGS = Flags(R[a] - sign_ext(imm6))
Flags
N, Z, V, C
COMP.F
Syntax
COMP.F Rb, [Ra], Size
Description
Subtract the contents of the address location specified by the
contents of register Ra from the contents of register Rb; set
the flags in register R7 according to the result of the
subtraction; discard the subtraction result.
Operation
R7_FLAGS = Flags(R[b] - sign_ext(FPI[R[a]]))
Flags
N, Z, V, C
COMP.PI
Syntax
COMP.PI Ra, [#offset6]
Description
Subtract the contents of the PRAM location specified by the
addition of contents of the PRAM Data Pointer, shifted left by
six bits, and the zero-extended 6-bit value offset6, from the
contents of register Ra; set the flags in register R7 according
to the result of the subtraction; discard the subtraction result.
Operation
R7_FLAGS = Flags(R[a] - PRAM[(DPTR<<6) +
zero_ext(#offset6)])
Flags
N, Z, V, C
