Freescale Semiconductor MCF5480 - Manual (Page 220)

MCF548x Reference Manual, Rev. 3
6-30 Freescale Semiconductor
values be moved into a table of constants that can be referenced using PC-relative addressing or as an offset
from another address pointer. See Table 6-29 .
Finally, ColdFire and the M68000 differ in how exceptions are made pending. In the ColdFire exception
model, asserting both an FPSR exception indicator bit and the corresponding FPCR enable bit makes an
exception pending. Thus, a pending exception state can be created by loading FPSR and/or FPCR. On the
M68000, this type of pending exception is not possible.
Analysis of compiled floating-point applications indicates these differences account for most of the
changes between M68000-compatible text and the equivalent ColdFire program.
Table 6-29. M68000/ColdFire Operation Sequence 3
M68000 ColdFire Equivalent
fadd.l #imm1,fp3 fadd.l (imm1_label,pc),fp3
fsub.s #imm2,fp4 fsub.s (imm2_label,pc),fp3
fdiv.d #imm3,fp5 fdiv.d (imm3_label,pc),fp3
align 4
imm1_label:
long imm1 ;integer longword
imm2_label:
long imm2 ;single-precision
imm3_label:
long imm3_upper,
imm3_lower ;double-precision