cpu_freq: extra timing loop WIP

diff --git a/avr/cmd_cpu.c b/avr/cmd_cpu.c
index 6f50a2a628fc57b6878cbbc8e4f07ed02a9e3e9c..61e3ec368718dcc13ff5b2e1703ca5fde288c152 100644 (file)
--- a/avr/cmd_cpu.c
+++ b/avr/cmd_cpu.c
@@ -32,26 +32,36 @@ static void test_delay(uint32_t count)
        while (get_timer(ts) <= count);
 }
 
-static int32_t z80_measure_phi(uint8_t cycles, bool input_clk, uint16_t wait_ms)
+static int32_t z80_measure_phi(uint8_t cycles, uint16_t wait_ms)
 {
        uint16_t ref_stop;
        uint16_t ref_ovfl;
        uint32_t x_freq;
+       uint8_t eimsk_save,eicrb_save;
 
 
+       ATOMIC_BLOCK(ATOMIC_FORCEON) {
+               /* Save state and disable INT6 */
+               eimsk_save = EIMSK;
+               EIMSK &= ~_BV(INT6);
+               /* Save state and set INT6 for falling edge */
+               eicrb_save = EICRB;
+               EICRB = (eicrb_save & ~(0b11 << ISC60)) | (0b10 << ISC60);
+       }
+
        PRR1 &= ~_BV(PRTIM3);
        TCCR3A = 0;
        TCCR3B = 0b000<<CS30;   /* stop counter */
        TCNT3 = 0;
        TIFR3 = _BV(TOV3);
        ref_ovfl = 0;
+
        ATOMIC_BLOCK(ATOMIC_FORCEON) {
                /* Reset pending int */
                EIFR = _BV(INTF6);
                /* Wait for falling edge */
                while ((EIFR & _BV(INTF6)) == 0)
                        ;
-               //ref_start = TCNT4;
                OCR4B = TCNT4;
                TCCR3B = 0b110<<CS30;   /* Count falling edges on T3 (==INT6) */
                TIFR4 = _BV(OCF4B);             /* clear compare match flag */
@@ -102,14 +112,12 @@ static int32_t z80_measure_phi(uint8_t cycles, bool input_clk, uint16_t wait_ms)
                if ((TIFR3 & _BV(TOV3)) != 0)
                        x_freq += 1UL << 16;
                uint32_t x_cnt = x_freq;
-               if (input_clk)                                          /* compute input clock */
-                       x_freq *= 2;
                x_freq *= cycles;
 
                x_freq = ((uint64_t) x_freq * F_CPU + (ref_cnt / 2))/ ref_cnt;
 
-               printf_P(PSTR("ref_start: %6u, ref_stop: %6u, ref_ovfl: %4u, ref_cnt: %9lu\n"
-                                         "    TCNT3: %6u,    x_cnt: %6lu, cycles: %3u, xfreq: %9lu\n"),
+               debug("ref_start: %6u, ref_stop: %6u, ref_ovfl: %4u, ref_cnt: %9lu\n"
+                                         "    TCNT3: %6u,    x_cnt: %6lu, cycles: %3u, xfreq: %9lu\n",
                                        OCR4B, ref_stop, ref_ovfl, ref_cnt,
                                        TCNT3, x_cnt, cycles, x_freq);
 
@@ -127,6 +135,19 @@ static int32_t z80_measure_phi(uint8_t cycles, bool input_clk, uint16_t wait_ms)
        TCCR3B = 0;
        PRR1 |= _BV(PRTIM3);
 
+       ATOMIC_BLOCK(ATOMIC_FORCEON) {
+               /* Restore INT6 */
+#if 0 /* wtf? */
+               eicrb_save = EICRB;
+               EICRB = (EICRB & ~(0b11 << ISC60)) | (eicrb_save & (0b11 << ISC60));
+#endif
+               EICRB = eicrb_save;
+               if ((eimsk_save & _BV(INT6)) != 0)
+                       EIMSK |= _BV(INT6);
+               /* Reset pending int */
+               EIFR = _BV(INTF6);
+       }
+
        return (int32_t) x_freq;
 }
 
@@ -315,6 +336,19 @@ command_ret_t do_busack_test(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED,
        return CMD_RET_SUCCESS;
 }
 
+static const FLASH uint8_t loop_code[] = {
+       /* 0000 */  0x01,0x36,0x00,             /* ld   bc,00*256+RCR                           */
+       /* 0003 */  0xAF,                       /* xor  a                                       */
+       /* 0004 */  0xED,0x79,          /* out  (c),a                                   */
+       /* 0006 */  0xD3,0x40,          /* out  (040H),a                                */
+       /*      */                              /*                                      ;Z80    Z180(0W) Z180(MaxW) */
+       /* 0008 */                              /* loop:                        ;-------------------------- */
+       /* 0008 */  0xDB,0x50           /* in   a,(050h)        ;11       10     +3*3  19   */
+       /* 000A */  0xC3,0x08,0x00      /* jp   loop            ;10                9     +3*3  18   */
+                                                                       /*                                      ;-------------------------- */
+                                                                       /*                                      ;21       19           37   */
+}
+
 command_ret_t do_cpu_freq(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int argc, char * const argv[])
 {
 
@@ -327,9 +361,7 @@ command_ret_t do_cpu_freq(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int
        uint8_t lcycles = 18;
        uint16_t timeout = 1000;
 
-       uint8_t eicrb_save;
-       uint8_t eimsk_save;
-       uint8_t mem_save[cpuinfo_length];
+       uint8_t mem_save[ARRAY_SIZE(loop_code)];
 
        /* reset getopt() */
        optind = 0;
@@ -368,22 +400,11 @@ command_ret_t do_cpu_freq(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int
                return CMD_RET_FAILURE;
        }
 
-       ATOMIC_BLOCK(ATOMIC_FORCEON) {
-               /* Save state and disable INT6 */
-               eimsk_save = EIMSK;
-               EIMSK &= ~_BV(INT6);
-               /* Save state and set INT6 for falling edge */
-               eicrb_save = EICRB;
-               EICRB = (eicrb_save & ~(0b11 << ISC60)) | (0b10 << ISC60);
-       }
 
        z80_bus_cmd(Request);
        if (options & O_LOAD_LOOP) {
-               z80_read_block(mem_save, 0, cpuinfo_length);
-               z80_load_mem(0, cpuinfo,
-                                       &cpuinfo_sections,
-                                       cpuinfo_address,
-                                       cpuinfo_length_of_sections);
+               z80_read_block(mem_save, 0, ARRAY_SIZE(loop_code));
+               z80_write_block_P(loop_code, 0, ARRAY_SIZE(loop_code));
        }
        Stat &= ~S_IO_0X40;                             /* Reset pending int */
        z80_bus_cmd(Release);
@@ -408,19 +429,9 @@ command_ret_t do_cpu_freq(cmd_tbl_t *cmdtp UNUSED, uint_fast8_t flag UNUSED, int
        z80_bus_cmd(Reset);
        if (options & O_UNLOAD_LOOP) {
                z80_bus_cmd(Request);
-               z80_write_block(mem_save, 0, cpuinfo_length);
+               z80_write_block(mem_save, 0, ARRAY_SIZE(loop_code));
                z80_bus_cmd(Release);
        }
-       ATOMIC_BLOCK(ATOMIC_FORCEON) {
-               /* Restore INT6 */
-               eicrb_save = EICRB;
-               EICRB = (EICRB & ~(0b11 << ISC60)) | (eicrb_save & (0b11 << ISC60));
-               if ((eimsk_save & _BV(INT6)) != 0)
-                       EIMSK |= _BV(INT6);
-               /* Reset pending int */
-               EIFR = _BV(INTF6);
-       }
-
        if (err)
                cmd_error(CMD_RET_FAILURE, err, NULL);
 

diff --git a/z180/freqloop.180 b/z180/freqloop.180
new file mode 100644 (file)
index 0000000..be1137d
--- /dev/null
+++ b/z180/freqloop.180
@@ -0,0 +1,20 @@
+       .z80                            ; for M80, ignored by SLR assembler\r
+       include z180reg.inc\r
+\r
+       aseg\r
+       org     0\r
+\r
+       ld      bc,00*256+RCR\r
+       xor     a\r
+       out     (c),a\r
+       out     (040H),a\r
+                               ;Z80    Z180(0W) Z180(MaxW)\r
+loop:                          ;--------------------------\r
+       in      a,(050h)        ;11       10     +3*3  19\r
+       jp      loop            ;10        9     +3*3  18\r
+                               ;--------------------------\r
+                               ;21       19           37\r
+\r
+       end\r
+\r
+; vim:set ts=8 noet nowrap\r