Computer Hardware User's Guide

Pop Floating-Point Value POPF
13-195 Assembly Language Instructions
Syntax POPF dst
Operation *SP–– → dst1
Operands dst register (R n , 0 ≤ n ≤ 7)
Opcode
31 24 23 16 8 7 015
000 01 0
1 11
dst 0
0
1
000 0000000000000
Description The top of the current system stack (32 MSBs) is popped and loaded into the
dst register. The top of the stack is assumed to be a floating-point number. The
POP is performed with a postdecrement of the stack pointer. The eight LSBs
of an extended-precision register (R7–R0) are zero-filled.
Cycles 1
Status Bits These condition flags are modified only if the destination register is R7–R0.
LUF Unaffected
UF 0
LV Unaffected
N 1 if a negative result is generated; 0 otherwise
Z 1 if a 0 result is generated; 0 otherwise
V 0
C Unaffected
OVM Operation is not affected by OVM bit value.
Example POPF R4
Before Instruction After Instruction
R4 02 5D2E 0123 R4 5F 2C13 0200
SP 80984A SP 809849
LUF 0 LUF 0
LV 0 LV 0
UF 0 UF 0
N 0 N 0
Z 0 Z 0
V 0 V 0
C 0 C 0
Data memory
80984Ah 5F2C1302 80984Ah 5F2C1302
6.91186578e+00
5.32544007e+28
5.32544007e+28
5.32544007e+28
Mode Bit