Freescale Semiconductor StarCore SC140 - Manual (Page 392)

A-78 SC140 DSP Core Reference Manual
BMCLR.W
BMCLR.W
Bit-Masked Clear a
BMCLR.W
16-Bit Operand in Memory (BMU)
Description
These operations use an unsigned 16-bit immediate data mask to clear selected bits in the destination
operand. For each bit i that is set (selected) in the mask, the bit i in the corresponding destination operand’s
bit position is cleared. These operations read from memory, modify the retrieved value, and write the new
value back to that memory address, resulting in two memory accesses. The absolute addresses, offsets, and
address register values must be word-aligned.
Status and Conditions that Affect Instruction
Status and Conditions Changed by Instruction
None.
Operation Assembler Syntax
0
→ (SP–u5)
i
(i denotes bits=1 in #u16)
BMCLR.W #u16,(SP–u5){0
≤ u16 < 2 16
<{0
≤ u5 < 64,W}
0
→ (SP+s16)
i
BMCLR.W #u16,(SP+s16){0
≤ u16 < 2 16
}{–2
15 ≤ s16 < 2 15
,W}
0
→ (Rn)
i
BMCLR.W #u16,(Rn){0
≤ u16 < 2 16
}
0
→ (a16)
i
BMCLR.W #u16,(a16){0
≤ u16 < 2 16
}{0
≤ a16 < 2 16
,W}
BMCLR.W #u16,(SP–u5)
Clears selected bits in the contents of a memory address pointed to by the active stack pointer (SP) with an
unsigned 5-bit offset.
BMCLR.W #u16,(SP+s16)
Clears selected bits in the contents of a memory address pointed to by the active stack pointer (SP) with a
16-bit signed offset.
BMCLR.W #u16,(Rn)
Selected bits in the contents of a memory address pointed to by an address register (Rn).
BMCLR.W #u16,(a16)
Clears selected bits in the contents of a memory address pointed to by an absolute 16-bit address.
Register Address Bit Name Description
SR[18] EXP Determines which stack pointer is used when the stack pointer is an
operand. Otherwise, the instruction is not affected by SR.