Instruction Cycle Times; The Bx Instruction - Samsung S3C2501X User Manual

INSTRUCTION SET
OP H1 H2 THUMB Assembler
00 0 1 ADD Rd, Hs
00 1 0 ADD Hd, Rs
00 1 1 ADD Hd, Hs
01 0 1 CMP Rd, Hs
01 1 0 CMP Hd, Rs
01 1 1 CMP Hd, Hs
10 0 1 MOV Rd, Hs
10 1 0 MOV Hd, Rs
00 0 1 MOV Hd, Hs
00 1 0 BX Rs
00 1 1 BX Hs

3.24.2 INSTRUCTION CYCLE TIMES

All instructions in this format have an equivalent ARM instruction as shown in Table 3-12. The instruction cycle
times for the THUMB instruction are identical to that of the equivalent ARM instruction.

3.24.3 THE BX INSTRUCTION

BX performs a branch to a routine whose start address is specified in a Lo or Hi register.
Bit 0 of the address determines the processor state on entry to the routine:
Bit 0 = 0 Causes the processor to enter ARM state.
Bit 0 = 1 Causes the processor to enter THUMB state.
The action of H1 = 1 for this instruction is undefined, and should not be used.
3-74
Table 3-12. Summary of Format 5 Instructions
ARM Equivalent
ADD Rd, Rd, Hs
ADD Hd, Hd, Rs
ADD Hd, Hd, Hs
CMP Rd, Hs
CMP Hd, Rs
CMP Hd, Hs
MOV Rd, Hs
MOV Hd, Rs
MOV Hd, Hs
BX Rs
BX Hs
NOTE
Action
Add a register in the range 8-15 to a register in
the range 0-7.
Add a register in the range 0-7 to a register in
the range 8-15.
Add two registers in the range 8-15.
Compare a register in the range 0-7 with a
register in the range 8-15. Set the condition
code flags on the result.
Compare a register in the range 8-15 with a
register in the range 0-7. Set the condition
code flags on the result.
Compare two registers in the range 8-15. Set
the condition code flags on the result.
Move a value from a register in the range 8-15
to a register in the range 0-7.
Move a value from a register in the range 0-7
to a register in the range 8-15.
Move a value between two registers in the
range 8-15.
Perform branch (plus optional state change) to
address in a register in the range 0-7.
Perform branch (plus optional state change) to
address in a register in the range 8-15.
S3C2501X