Imlpemented RTI. Testing RTS and FIXED test for BL.

epiphany/execute_branch.py

@@ -21,7 +21,7 @@ def execute_bcond(s, inst):
         cond = inst.cond
         imm = inst.bcond_imm
         if cond == 0b1111:  # Branch and link (BL).
-            s.rf[epiphany.isa.reg_map['LR']] = s.pc + 2 if is16bit else s.pc + 4
+            s.rf[epiphany.isa.reg_map['LR']] = (s.pc + 2) if is16bit else (s.pc + 4)
         if should_branch(s, cond):
             s.pc += (sext_8(signed_8(imm)) << 1) if is16bit else (sext_24(signed_24(imm)) << 1)
         else:

epiphany/execute_interrupt.py

@@ -72,7 +72,16 @@ def execute_sync16(s, inst):
 # rti16
 #-----------------------------------------------------------------------
 def execute_rti16(s, inst):
-    raise NotImplementedError('Interrupts not implemented.')
+    """
+    IPEND[_i_] = 0; where _i_ is the current interrupt level being serviced
+    STATUS[1] = 0;
+    PC = IRET;
+    <execute instruction at PC>
+    """
+    # FIXME: Set IPEND.
+    mask = 0xFFFFFFFD
+    s.rf[epiphany.isa.reg_map['STATUS']] &= mask
+    s.pc = s.rf[epiphany.isa.reg_map['IRET']]
 
 
 #-----------------------------------------------------------------------

epiphany/test/asm/bl.S

@@ -1,18 +1,20 @@
 #include "epiphany-macros.h"
 SET_UP
-    ; Temporary register - r14
-    ; Function argument  - r15
-    ; Function return    - r16
-    mov r15, #5
-    mov r16, #0
+    ; Temporary register - r0
+    ; Function argument  - r1
+    ; Function return    - r2
+    mov r1, #5
+    mov r2, #0
     bl _my_func ; save PC to LR and jump to _my_func
-    TEAR_DOWN  ; Sets breakpoint.
+    b _end
     _my_func:
-        mov r14, #0
-        mov r16, #0
+        mov r0, #0
+        mov r2, #0
         _loop:
-            add r14, r14, r15
-            sub r15, r15, #1
+            add r0, r0, r1
+            sub r1, r1, #1
             bne _loop
-        add r16, r16, r14
-    rts  ; branch back to callee
+        add r2, r0, #0
+        rts  ; branch back to callee
+    _end:
+TEAR_DOWN  ; Sets breakpoint.

epiphany/test/asm/rts.S

@@ -1,4 +1,14 @@
 #include "epiphany-macros.h"
 SET_UP
-    rts
+    bl _my_func ; save PC to LR and jump to _my_func
+    nop
+    nop
+    nop
+    b _end
+    _my_func:
+        mov r1, #100
+        mov r2, #200
+        add r3, r1, r2
+        rts  ; branch back to callee
+    _end:
 TEAR_DOWN

epiphany/test/test_asm.py

@@ -14,7 +14,7 @@
         ('asr.elf', StateChecker(pc=(10 +  + RESET_ADDR), rf0=1, rf1=5, rf2=0, rf3=0)),
         ('bcond.elf', StateChecker(pc=(12 + RESET_ADDR), rf0=0, rf1=110)),
         ('bitr.elf', StateChecker(pc=(6 + RESET_ADDR), rf0=170, rf1=85)),
-        ('bl.elf', StateChecker(rf14=15, rf15=0, rf16=15)),
+        ('bl.elf', StateChecker(pc=114, rf0=15, rf1=0, rf2=15)),
         pytest.mark.xfail(('dma_transfer.elf', StateChecker())),
         ('eor.elf', StateChecker(pc=(8 + RESET_ADDR), rf0=5, rf1=7, rf2=2)),
         ('fix.elf', StateChecker(pc=(8 + RESET_ADDR), rf0=5)),
@@ -35,7 +35,7 @@
         ('nop.elf', StateChecker(pc=(4 + RESET_ADDR))),
         ('orr.elf', StateChecker(pc=(8 + RESET_ADDR), rf0=5, rf1=7, rf2=7)),
         pytest.mark.xfail(('rti.elf', StateChecker())),
-        pytest.mark.xfail(('rts.elf', StateChecker())),
+        ('rts.elf', StateChecker(pc=110, rf1=100, rf2=200, rf3=300, rfLR=90)),
         ('sub.elf', StateChecker(pc=(12 + RESET_ADDR), rf0=100, rf1=20, rf2=80, rf3=80)),
         pytest.mark.xfail(('trap.elf', StateChecker(pc=(6 + RESET_ADDR)))),
        ])

epiphany/test/test_execute_interrupt.py

@@ -59,8 +59,16 @@ def test_execute_bkpt16():
     assert not state.running
 
 
-@pytest.mark.parametrize('name,instr', [('rti16',  opcode_factory.rti16()),
-                                        ('trap16', opcode_factory.trap16(0b111111))])
+def test_execute_rti16():
+    state = new_state(rfIRET=224, rfSTATUS=0b10, pc=0)
+    instr = opcode_factory.rti16()
+    name, executefn = decode(instr)
+    executefn(state, Instruction(instr, None))
+    expected_state = StateChecker(pc=224, rfIRET=224, rfSTATUS=0b00)
+    expected_state.check(state)
+
+
+@pytest.mark.parametrize('name,instr', [('trap16', opcode_factory.trap16(0b111111))])
 def test_execute_interrupt_instructions(name, instr):
     with pytest.raises(NotImplementedError):
         state = new_state()