Vault 7: Projects
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16-bit MCU and DSC Programmer’s Reference Manual
DS70157F-page 160 © 2005-2011 Microchip Technology Inc.
BTSC
Bit Test f, Skip if Clear
Implemented in: PIC24F PIC24H PIC24E dsPIC30F dsPIC33F dsPIC33E
X X X X X X
Syntax: {label:} BTSC{.B} f, #bit4
Operands: f ∈ [0 ... 8191] for byte operation
f ∈ [0 ... 8190] (even only) for word operation
bit4 ∈ [0 ... 7] for byte operation
bit4 ∈ [0 ... 15] for word operation
Operation: Test (f)<bit4>, skip if clear
Status Affected: None
Encoding: 1010 1111 bbbf ffff ffff fffb
Description: Bit ‘bit4’ in the file register is tested. If the tested bit is ‘0’, the next
instruction (fetched during the current instruction execution) is discarded
and on the next cycle, a NOP is executed instead. If the tested bit is ‘1’,
the next instruction is executed as normal. In either case, the contents of
the file register are not changed. For the bit4 operand, bit numbering
begins with the Least Significant bit (bit 0) and advances to the Most
Significant bit (bit 7 for byte operations, bit 15 for word operations).
The ‘b’ bits select value bit4, the bit position to test.
The ‘f’ bits select the address of the file register.
Note 1: The extension .B in the instruction denotes a byte operation
rather than a word operation. You may use a .W extension to
denote a word operation, but it is not required.
2: When this instruction operates in Word mode, the file register
address must be word-aligned.
3: When this instruction operates in Byte mode, ‘bit4’ must be
between 0 and 7.
Words: 1
Cycles:
1 (2 or 3)
(1)
Note 1:
In dsPIC33E and PIC24E devices, the listed cycle count does not apply to read and
read-modify-write operations on non-CPU Special Function Registers. For more
details, see
Note 3
in
Section 3.2.1 “Multi-Cycle Instructions”
.
Example 1:
002000 HERE: BTSC.B 0x1201, #2
002002 GOTO BYPASS
002004 . . .
002006 . . .
002008 BYPASS: . . .
00200A . . .
; If bit 2 of 0x1201 is 0,
; skip the GOTO
Before
Instruction
After
Instruction
PC 00 2000 PC 00 2002
Data 1200 264F Data 1200 264F
SR 0000 SR 0000
Protego_Release_01_05-Related-OEM-Documentation-PIC24FJ64GA004-Programmers_Reference_Manual.pdf