Differences

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--- useful_programs [2019/06/20 11:20] – [Detecting rise / fall edge of the signals] emozolyak
+++ useful_programs [2019/09/17 08:23] – [Bit functions] emozolyak
@@ Line 22: / Line 22: @@
 To access idividual bits, you can use following handy functions:
 <code lua>
--- to check, set,clear individual bits in numbers
 function bw(n)
   return 2 ^ (n - 1)  -- returns weight of the bit in pos. n
 end
-function hasbit(x, p)
+function hasbit(x, b)
-  return x % (p + p) >= p  -- returns if p is true/false; if hasbit(value, bw(2)) then ...
+  local p = bw(b)
+  return x % (p + p) >= p  -- returns if b is true/false; if hasbit(value, b) then ...
 end
-function setbit(x, p)
+function setbit(x, b)
-  return hasbit(x, p) and x or x + p -- sets bit #p in х example:  х = setbit(х, bit(p))
+  return hasbit(x, b) and x or x + bw(b) -- sets bit b in х example:  х = setbit(х, b))
 end
-function clearbit(x, p)
+function clearbit(x, b)
-  return hasbit(x, p) and x - p or x --  clears bit #p in х
+  return hasbit(x, b) and x - bw(b) or x --  clears bit b in х
 end
-function togglebit(x, b) -- toggles bit #b in x
+function togglebit(x, b) -- toggles bit b in x
-    local r
+    if hasbit(x, b) then
+        return clearbit(x, b)
-    if hasbit(x,bw(b)) then
-        r = clearbit(x, bw(b))
     else
-        r = setbit(x, bw(b))
+        return setbit(x, b)
     end
-    return r
 end
--- output bool conditoin as 0 /1 into a bit
+function outbit(condition, x, b) -- output bool condition as 0 /1 into a bit
-function outbit(x, p, condition)
+     if condition then
-     if condition   then
+         return hasbit(x, b) and x or x + bw(b)
-         return hasbit(x, p) and x or x + p -- sets bit #p in х example:  х = setbit(х, bw(p))
      else
-         return hasbit(x, p) and x - p or x --  clears bit #p in х
+         return hasbit(x, b) and x - bw(b) or x
      end
 end
--- uses alias and sets bit in it
+function outBit(condition, alias, b) -- output bool condition as 0 /1 into a bit of a internal register
-function setBit(alias, b)
+     local new_value = outbit(condition, R(alias), b)
-    local value = R(alias)
+     W(alias, new_value)
-    value = setbit(value, bw(b))
-    W(alias, value)
 end
+function setBit(alias, b) -- sets bit in the register using alias or id
+    local old_value = R(alias)
+    local new_value = setbit(old_value, b)
--- uses alias and crears bit in it
+    if (new_value ~= old_value) then
-function clearBit(alias, b)
+        WriteReg(alias, new_value)  -- to prevent unnecessary writing
-    local value = R(alias)
+    end
-    value = clearbit(value, bw(b))
-    W(alias, value)
 end
+function clearBit(alias, b) -- uses alias or id and crears bit in it
+    local old_value = R(alias)
+    local new_value = clearbit(old_value, b)
+    if (new_value ~= old_value) then
+        WriteReg(alias, new_value)
+    end
+end
+function toggleBit(alias, b) -- toggles bit b in reg by alias or id
+     local cur_value = R(alias)
+    if hasbit(cur_value, b) then
+        clearBit(alias, b)
+    else
+        setBit(alias, b)
+    end
+    return true
+end
 -- return bit from the position as a  1 / 0
-function getBit(x, p)
+function getBit(alias, b)
-    if hasbit ( x , p) then
+    if hasbit(R(alias), b) then
         return 1
     else
@@ Line 122: / Line 140: @@
 <code lua>
-function DBG ( ... )
+function DBG( ...) -- ... accepts multiple arguments in a table arg
-            -- ... means variable number of arguments in lua, passed in the 'arg' table
+local table_sign = '|' -- if there is divider sign, the values will be grouped in 2 rows
+local table_sign_found = false
+local tab_s_index = 0
 if ENABLE_DEBUG then -- should be global in the calling script
+    -- find divider
+    for i = 1, #arg do
+        if arg[i] == table_sign then
+            table_sign_found = true
+            tab_s_index = i
+            break
+        end
+    end
-    local s = ""            -- string buffer to concatenate all arguments
+    if not table_sign_found then
-        for i = 1 , #arg do
+        INFO(tabToStr(arg)) -- outputs table values in a single row
-        -- glue all and add spaces, use tostring to protect from nil argument
+    else
-            s = s .. tostring ( arg [i]  ) .. ' '
+        local header_t, value_t = {}, {} -- prepare header and value rows
+        for k = 1, tab_s_index - 1 do
+            header_t[k] = arg[k]
         end
-    DEBUG ( s )
+        for j = tab_s_index + 1, #arg do
-end -- if
+            value_t[j - tab_s_index] = tostring(arg[j])
+        end
+        if (#header_t ~= #value_t) then
+             ERROR("column count differs!")
+        else
+            for g = 1, #header_t do
+                local delta = #header_t[g] - #value_t[g] -- makes aligment by adding spaces to shorter strings...
+                if delta ~= 0 then
+                    if (delta > 0) then
+                        value_t[g] = value_t[g] .. string.rep(' ', delta)
+                    else
+                        header_t[g] = header_t[g] .. string.rep(' ', math.abs(delta))
+                    end
+                end
+            end -- for
+            INFO(tabToStr(header_t)) ; INFO(tabToStr(value_t))
+        end
+    end
+end -- if ENABLE_DEBUG
+return true
+end -- DBG
+function tabToStr(t)  -- glue all and add spaces, use tostring to protect from nil and bool argument
+    local s = ""
+    for i = 1, #t do
+        s = s .. tostring(t[i]) .. ' '
+    end -- for
+    return s
+end
-end -- DBG
 </code>
+Then the print output can be enhanced like this:
+{{ :dbg_table_out.png?direct&600 |}}
 The //ENABLE_DEBUG// flag should be global boolean variable in the calling script. You may just to set it when needed and save the script.