try another layout

zacas.adoc

@@ -30,22 +30,6 @@ operation performed by `AMOCAS.W` for RV32 is as follows:
  X(rd) = temp
 ----
 
-For RV64, `AMOCAS.W` atomically loads a 32-bit data value from address in
-`rs1`, compares the loaded value to the lower 32 bits of the value held in `rd`,
-and if the comparison is bitwise equal, then stores the lower 32 bits of the
-value held in `rs2` to the original address in `rs1`. The 32-bit value loaded
-from memory is sign-extended and is placed into register `rd`. The operation
-performed by `AMOCAS.W` for RV64 is as follows:
-
-[listing]
-----
- temp[31:0] = mem[X(rs1)]
- if ( temp[31:0] == X(rd)[31:0] )
- mem[X(rs1)] = X(rs2)[31:0]
- endif
- X(rd) = SignExtend(temp[31:0])
-----
-
 `AMOCAS.D` is similar to `AMOCAS.W` but operates on 64-bit data values.
 
 For RV32, `AMOCAS.D` atomically loads 64-bits of a data value from address in
@@ -61,7 +45,6 @@ register of a destination register pair is `x0`, then the entire register
 result is discarded and neither destination register is written.
 The operation performed by `AMOCAS.D` for RV32 is as follows:
 [listing]
-----
  temp0 = mem[X(rs1)+0]
  temp1 = mem[X(rs1)+4]
  comp0 = (rd == x0) ? 0 : X(rd)
@@ -76,21 +59,33 @@ The operation performed by `AMOCAS.D` for RV32 is as follows:
  X(rd) = temp0
  X(rd+1) = temp1
  endif
-----
+
+For RV64, `AMOCAS.W` atomically loads a 32-bit data value from address in
+`rs1`, compares the loaded value to the lower 32 bits of the value held in `rd`,
+and if the comparison is bitwise equal, then stores the lower 32 bits of the
+value held in `rs2` to the original address in `rs1`. The 32-bit value loaded
+from memory is sign-extended and is placed into register `rd`. The operation
+performed by `AMOCAS.W` for RV64 is as follows:
+
+[listing]
+ temp[31:0] = mem[X(rs1)]
+ if ( temp[31:0] == X(rd)[31:0] )
+ mem[X(rs1)] = X(rs2)[31:0]
+ endif
+ X(rd) = SignExtend(temp[31:0])
 
 For RV64, `AMOCAS.D` atomically loads 64-bits of a data value from address in
 `rs1`, compares the loaded value to a 64-bit value held in `rd`, and if the
 comparison is bitwise equal, then stores the 64-bit value held in `rs2` to the
 original address in `rs1`. The value loaded from memory is placed into register
 `rd`. The operation performed by `AMOCAS.D` for RV64 is as follows:
 [listing]
-----
  temp = mem[X(rs1)]
  if ( temp == X(rd) )
  mem[X(rs1)] = X(rs2)
  endif
  X(rd) = temp
-----
+
 `AMOCAS.Q` (RV64 only) atomically loads 128-bits of a data value from address in
 `rs1`, compares the loaded value to a 128-bit value held in a register pair
 consisting of `rd` and `rd+1`, and if the comparison is bitwise equal, then
@@ -104,7 +99,6 @@ destination register pair is `x0`, then the entire register result is discarded
 and neither destination register is written. The operation performed by
 `AMOCAS.Q` is as follows:
 [listing]
-----
  temp0 = mem[X(rs1)+0]
  temp1 = mem[X(rs1)+8]
  comp0 = (rd == x0) ? 0 : X(rd)
@@ -119,7 +113,7 @@ and neither destination register is written. The operation performed by
  X(rd) = temp0
  X(rd+1) = temp1
  endif
-----
+
 [NOTE]
 ====
 For a future RV128 extension, `AMOCAS.Q` would encode a single XLEN=128 register
@@ -148,7 +142,6 @@ data value for its comparison.
 The following example code sequence illustrates the use of `AMOCAS.D` in a RV32
 implementation to atomically increment a 64-bit counter.
 [listing]
-----
 # a0 - address of the counter.
 increment:
  lw a2, (a0) # Load current counter value using
@@ -163,14 +156,19 @@ retry:
  bne a2, a6, retry # If amocas.d failed then retry
  bne a3, a7, retry # using current values loaded by amocas.d.
  ret
-----
+====
+
+<<<
+
+[NOTE]
+====
 The following example code sequence illustrates the use of `AMOCAS.Q` to
 implement the _enqueue_ operation for a non-blocking concurrent queue using the
 algorithm outlined in cite:[queue]. The algorithm atomically operates on a
 pointer and its associated modification counter using the `AMOCAS.Q` instruction
 to avoid the ABA problem.
+
 [listing]
-----
 # Enqueue operation of a non-blocking concurrent queue.
 # Data structures used by the queue:
 # structure pointer_t {ptr: node_t *, count: uint64_t}
@@ -202,7 +200,7 @@ move_tail: # Tail was not pointing to the last node
  addi a3, a3, 1 # Try to swing Tail to the next node
  amocas.q.aqrl a6, a2, (a0)
  j enqueue # Retry
-----
+
 ====
 
 == Additional AMO PMAs