Computer Hardware User's Guide

PUSH Floating-Point Value PUSHF
13-197 Assembly Language Instructions
Syntax PUSHF src
Operation src → *++SP
Operands src register (R n , 0 ≤ n ≤ 7)
Opcode
31 24 23 16 8 7 015
000 01 1
1 11
src 0
0
1
0000000000 0000 00
Description The contents of the src register (32 MSBs) are pushed on the current system
stack. The
src is assumed to be a floating-point number. The PUSH is per-
formed with a preincrement of the stack pointer. The eight LSBs of the mantis-
sa are not saved. (Note the difference in R2 and the value on the stack in the
example below.)
Cycles 1
Status Bits LUF Unaffected
LV Unaffected
UF Unaffected
N Unaffected
Z Unaffected
V Unaffected
C Unaffected
OVM Operation is not affected by OVM bit value.
Example PUSHF R2
Before Instruction After Instruction
R2 02 5C12 8081 R2 02 5C12 8081
SP 809801 SP 809802
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
809802h 0 809802h 025C1280
6.87725854e+00
6.87725830e+00
6.87725854e+00
Mode Bit