Zcmp extension: review comments and bugfix (spimm support fix)

Signed-off-by: Albert Yosher <[email protected]>

Author: ayosher

arch/inst/Zcmp/cm.pop.yaml

@@ -7,15 +7,6 @@ long_name: Destroy function call stack frame
 description: |
   Destroy stack frame: load `ra` and 0 to 12 saved registers from the stack frame, deallocate the stack frame.
   This instruction pops (loads) the registers in `reg_list` from stack memory, and then adjusts the stack pointer by `stack_adj`.
-  --
-
-  Stack Adjustment Calculation:
-
-  --
-  `stack_adj_base` is the minimum number of bytes, in multiples of 16-byte address increments, required to cover the registers in the list.
-  `spimm` is the number of additional 16-byte address increments allocated for the stack frame.
-  The total stack adjustment represents the total size of the stack frame, which is `stack_adj_base` added to `spimm` scaled by 16, as defined above.
-  --
 
   Restrictions on stack_adj:
 
@@ -35,6 +26,7 @@ encoding:
       not: [0, 1, 2, 3]
     - name: spimm
       location: 3-2
+      left_shift: 4
 access:
   s: always
   u: always
@@ -47,10 +39,9 @@ operation(): |
 
   XReg size = xlen();
   XReg nreg = (rlist == 15) ? 13 : (rlist - 3);
-  XReg stack_additional_adj = (spimm * 16);
   XReg stack_aligned_adj = (nreg * 4 + 15) & ~0xF;
   XReg virtual_address_sp = X[2];
-  XReg virtual_address_new_sp = virtual_address_sp + stack_aligned_adj + stack_additional_adj;
+  XReg virtual_address_new_sp = virtual_address_sp + stack_aligned_adj + spimm;
   XReg virtual_address_base = virtual_address_new_sp - (nreg * size);
 
   X[ 1] = read_memory_xlen(virtual_address_base +  0*size, $encoding);

arch/inst/Zcmp/cm.popret.yaml

@@ -7,15 +7,6 @@ long_name: Destroy function call stack frame and return to `ra`.
 description: |
   Destroy stack frame: load `ra` and 0 to 12 saved registers from the stack frame, deallocate the stack frame, return to `ra`.
   This instruction pops (loads) the registers in `reg_list` from stack memory, and then adjusts the stack pointer by `stack_adj` and then return to `ra`.
-  --
-
-  Stack Adjustment Calculation:
-
-  --
-  `stack_adj_base` is the minimum number of bytes, in multiples of 16-byte address increments, required to cover the registers in the list.
-  `spimm` is the number of additional 16-byte address increments allocated for the stack frame.
-  The total stack adjustment represents the total size of the stack frame, which is `stack_adj_base` added to `spimm` scaled by 16, as defined above.
-  --
 
   Restrictions on stack_adj:
 
@@ -35,6 +26,7 @@ encoding:
       not: [0, 1, 2, 3]
     - name: spimm
       location: 3-2
+      left_shift: 4
 access:
   s: always
   u: always
@@ -47,10 +39,9 @@ operation(): |
 
   XReg size = xlen();
   XReg nreg = (rlist == 15) ? 13 : (rlist - 3);
-  XReg stack_additional_adj = (spimm * 16);
   XReg stack_aligned_adj = (nreg * 4 + 15) & ~0xF;
   XReg virtual_address_sp = X[2];
-  XReg virtual_address_new_sp = virtual_address_sp + stack_aligned_adj + stack_additional_adj;
+  XReg virtual_address_new_sp = virtual_address_sp + stack_aligned_adj + spimm;
   XReg virtual_address_base = virtual_address_new_sp - (nreg * size);
 
   X[ 1] = read_memory_xlen(virtual_address_base +  0*size, $encoding);

arch/inst/Zcmp/cm.popretz.yaml

@@ -7,15 +7,6 @@ long_name: Destroy function call stack frame, move zero to `a0` and return to `r
 description: |
   Destroy stack frame: load `ra` and 0 to 12 saved registers from the stack frame, deallocate the stack frame, move zero to `a0`, return to `ra`.
   This instruction pops (loads) the registers in `reg_list` from stack memory, and then adjusts the stack pointer by `stack_adj`, move zero to `a0` and then return to `ra`.
-  --
-
-  Stack Adjustment Calculation:
-
-  --
-  `stack_adj_base` is the minimum number of bytes, in multiples of 16-byte address increments, required to cover the registers in the list.
-  `spimm` is the number of additional 16-byte address increments allocated for the stack frame.
-  The total stack adjustment represents the total size of the stack frame, which is `stack_adj_base` added to `spimm` scaled by 16, as defined above.
-  --
 
   Restrictions on stack_adj:
 
@@ -35,6 +26,7 @@ encoding:
       not: [0, 1, 2, 3]
     - name: spimm
       location: 3-2
+      left_shift: 4
 access:
   s: always
   u: always
@@ -47,10 +39,9 @@ operation(): |
 
   XReg size = xlen();
   XReg nreg = (rlist == 15) ? 13 : (rlist - 3);
-  XReg stack_additional_adj = (spimm * 16);
   XReg stack_aligned_adj = (nreg * 4 + 15) & ~0xF;
   XReg virtual_address_sp = X[2];
-  XReg virtual_address_new_sp = virtual_address_sp + stack_aligned_adj + stack_additional_adj;
+  XReg virtual_address_new_sp = virtual_address_sp + stack_aligned_adj + spimm;
   XReg virtual_address_base = virtual_address_new_sp - (nreg * size);
 
   X[ 1] = read_memory_xlen(virtual_address_base +  0*size, $encoding);

arch/inst/Zcmp/cm.push.yaml

@@ -10,15 +10,6 @@ description: |
   and then creates the stack frame by decrementing the stack pointer by `stack_adj`,
   including any additional stack space requested by the value of `spimm`.
   The `spimm` could be 0, 1, 2 or 3 corresponding to additional stack allocated size of 0, 16, 32 or 48 bytes.
-  --
-
-  Stack Adjustment Calculation:
-
-  --
-  `stack_adj_base` is the minimum number of bytes, in multiples of 16-byte address increments, required to cover the registers in the list.
-  `spimm` is the number of additional 16-byte address increments allocated for the stack frame.
-  The total stack adjustment represents the total size of the stack frame, which is `stack_adj_base` added to `spimm` scaled by 16, as defined above.
-  --
 
   Restrictions on stack_adj:
 
@@ -38,6 +29,7 @@ encoding:
       not: [0, 1, 2, 3]
     - name: spimm
       location: 3-2
+      left_shift: 4
 access:
   s: always
   u: always
@@ -50,10 +42,9 @@ operation(): |
 
   XReg size = xlen();
   XReg nreg = (rlist == 15) ? 13 : (rlist - 3);
-  XReg stack_additional_adj = (spimm * 16);
   XReg stack_aligned_adj = (nreg * 4 + 15) & ~0xF;
   XReg virtual_address_sp = X[2];
-  XReg virtual_address_new_sp = virtual_address_sp - stack_aligned_adj - stack_additional_adj;
+  XReg virtual_address_new_sp = virtual_address_sp - stack_aligned_adj - spimm;
   XReg virtual_address_base = virtual_address_sp - (nreg * size);
 
   write_memory_xlen(virtual_address_base +  0*size, X[ 1], $encoding);