Zxt.x, Zero extension (dalu), Description – Freescale Semiconductor StarCore SC140 User Manual
Page 742: Status and conditions that affect instruction, Example 2, Operation assembler syntax
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SC140 DSP Core Reference Manual
ZXT.x
ZXT.x
Zero Extension (DALU)
ZXT.x
Description
These operations zero-extend a data register.
Status and Conditions that Affect Instruction
None.
Status and Conditions Changed by Instruction
Example 1
zxt.b d2,d5
Example 2
zxt.w d3,d6
Operation
Assembler Syntax
Da[7:0]
→ Dn[7:0]; 0 → Dn[39:8]
ZXT.B Da,Dn
Da[15:0]
→ Dn[15:0]; 0 → Dn[39:16]
ZXT.W Da,Dn
0
→ Dn[39:32]
ZXT.L Dn
ZXT.B Da,Dn
Copies bits [7:0] from a source data register (Da) to a 40-bit destination data register (Dn) and zero-extends
bits [39:8] of Dn.
ZXT.W Da,Dn
Copies bits [15:0] from a source data register (Da) to a 40-bit destination data register (Dn) and
zero-extends bits [39:16] of Dn.
ZXT.L Dn
Zero-extend a long word from bit 32 through the remaining upper bits in a 40-bit data register (Dn).
Register Address
Bit Name
Description
Ln
L
Clears the Ln bit in the destination register.
Register/Memory Address
Before
After
D2
$00 46EA 8BE8
L5:D5
$0:$00 0000 00E8
Register/Memory Address
Before
After
D3
$FF A836 5EC4