v0.4.0rc0

Author: nerdralph

src/ArduinoShrink.h

@@ -12,3 +12,21 @@ inline void delayMicroseconds(unsigned int us)
     _delay_us(us);
 }
 
+extern "C" uint32_t micros_raw();
+inline uint32_t micros()
+{
+    /*
+    register uint32_t micros_ asm("r22");
+    asm ("call micros_raw" : "=r" (micros_) );
+    return micros_;
+    */
+    // asm volatile ("call micros_raw");
+    return micros_raw() * 4;
+}
+
+extern "C" uint32_t millis_raw();
+inline uint32_t millis()
+{
+    uint32_t m = millis_raw();
+    return m + ((m * 1573) >> 16);
+}

src/macros.inc

@@ -0,0 +1,5 @@
+
+.macro GLABEL name
+     .global \name
+     \name:
+.endm

src/micros.S

@@ -11,10 +11,11 @@
 ;} t0_millis;
 
 
-;.global lsl4_r22_r30
+; to force t0_isr to get linked in
+.global t0_ovfl_isr
 
-.global micros
-micros:
+.global micros_raw
+micros_raw:
     ldi ZL, lo8(t0_millis)
     ldi ZH, hi8(t0_millis)
 1:
@@ -25,6 +26,4 @@ micros:
     in r0, TCNT0
     sub r0, r22                         ; TCNT0 overflow?
     brcs 1b
-    ldi r30, 2                          ; multiply by micros/tick
-    rcall lsl4_r22_r30
 ret

src/millis.S

@@ -9,38 +9,18 @@
 ;} t0_millis;
 
 ; to force t0_isr to get linked in
-.global lsl4_r22_r20
+.global t0_ovfl_isr
 
-.global millis
-millis:
+.global millis_raw
+millis_raw:
     ldi ZL, lo8(t0_millis)
     ldi ZH, hi8(t0_millis)
+1:
     ld r22, Z
     ldd r23, Z+1
     ldd r24, Z+2
     ldd r25, Z+3
     ld r0, Z
     cp r0, r22                          ; has millis changed?
-    brne millis
-    ; millis = t0_ovfl * 1.024 , so multiply by fractional addition
-    movw r18, r22
-    movw r20, r24
-    rcall shift_add                     ; adds t0_ovfl / 128
-    rcall shift_add                     ; adds t0_ovfl / 64
-    ; rcall 1f
-    ; todo: add t0_ovfl / 2048
-1:  add r18, r24                        ; adds t0_ovfl / 16384
-    adc r19, r25
-    adc r20, r1
-    movw r22, r18
-    movw r24, r20
-ret
-
-shift_add:
-    ldi r30, 1
-    rcall lsl4_r22_r30
-    add r18, r23
-    adc r19, r24
-    adc r20, r25
-    adc r21, r1
+    brne 1b
 ret

src/millis.c

@@ -20,3 +20,4 @@ void init_millis()
     TCCR0B = _BV(CS01) | _BV(CS00);     // div64 prescaler
     TIMSK0 = _BV(TOIE0);                // enable overflow interrupt
 }
+

src/t0_ovfl_isr.S

@@ -2,14 +2,17 @@
 ; ArduinoShrink
 
 #include <avr/io.h>
+#include "macros.inc"
 
 ;struct {
 ;    uint32_t t0_ovfl;
 ;    uint8_t ovfl_pad;
 ;} t0_millis;
 
-.global TIMER0_OVF_vect
-TIMER0_OVF_vect:
+; to help with linking
+GLABEL t0_ovfl_isr
+
+GLABEL TIMER0_OVF_vect
     push r16
     in r16, SREG-0x20
     push r16
@@ -29,13 +32,3 @@ t0_ovfl_inc:
     pop r16
 reti
 
-; shift left r22-r25 (ulong), arg in r30
-.global lsl4_r22_r30
-lsl4_r22_r30:
-    lsl r22
-    rol r23
-    rol r24
-    rol r25
-    dec r30
-    brne lsl4_r22_r30
-ret