SCP: Enable C99 standard 'bool'

Teach SIMH to make use of the C standard bool type when supported,
implemented in the support/sim_bool.h header.

  - If the compiler claims that __STDC_VERSION__ is C99 and above, or
    if the Microsoft C compiler version is at least 1800, include
    stdbool.h, typedef t_bool to bool, set TRUE and FALSE to true and
    false, respectively.

  - If not a standard compliant compiler or older Microsoft compiler,
    typedef t_bool to int, TRUE = 1 and FALSE = 0 (i.e., the old SIMH
    settings.)

CMake: Use target_compiler_feature() to baseline C99 dialect.

Make a pass through the SIMH code base for t_bool variable declarations
and associated references:

  - Ensure boolean expressions are boolean expressions, e.g.,
    "(foo & mask) != 0" vs. "foo & mask" to remove any ambiguity.
    Overkill, perhaps, but explicitly and unambiguously Boolean.

  - Fix expressions, declarations where t_bool was assumed to be the
    same as int.

  - Fix inconsistent function prototypes.

3B2:

  3b2_mau.h: Adjust *_SIGN() macros to produce Boolean expressions.

AltairZ80:

  s100_dazzler.c: Change daz_0e, daz_0f and daz_frame's type from t_bool to
      uint8, remove assumption that t_bool is type-equivalent to int.

  m68k/m68k.h, m68k/m68kcpu.c: Rename TRUE to NMI_TRUE, FALSE to NMI_FALSE
    to resolve namespace collision with SIMH TRUE and FALSE.

H316:

  h316_hi.c, h316_mi.c: Ensure assignment result is Boolean.

  hp2100_defs.h, FLIP_FLOP enum: Alias CLEAR and SET to FALSE and TRUE,
      respectively, to avoid any compiler ambiguity with respect to
      Boolean values.

  hp2100_sys.c: Update assignment to Boolean result.

HP3000:

  hp3000_lp.c: Ensure (device_command ^ J2W10_INSTALLED) evaluates to a
      Boolean expression. Instantiates a separate boolean variable to
      preserve comment formatting.

I1401:

  i1401_cpu.c: Initialize clear to FALSE (vice 0), ensure conv_old is
      assigned a Boolean value in cpu_set_conv() (t_bool is not int32.)

  i1401_iq.c: Assign use_h from a Boolean expression.

  i1401_sys.c: Assign use_h from a Boolean expression in dcw() and
      fprint_sym().

I7094:

  Fix ch6_req_wr() return type: should be t_bool, not t_stat.

Ibm1130:

  ibm1130_cr.c: Remove extraneous extern declaraction for cgi.

  ibm1130_defs.h: Change cgi and cgiwritable's extern declaration type to
      t_bool to be consistent with actual definitions.

  ibm1130_disk.c: Assign raw_disk_debug from a Boolean expression.

  ibm1139_gui.c: Update update_gui() prototype to be consistent across the
      GUI and non-GUI compile paths.

  ibm1130_sca.c: Assign any_timer_running from a Boolean expression.

  ibm1130_stddev.c: Remove extraneous extern declaraction for cgi.

  t_bool for update_gui

Interdata:

  id_idc.c: Fix idc_wds() return type (was t_stat, should be t_bool.)

ND100:

  nd100_sys.c: Update sim_load()'s flag declaration. Should be int, not
      t_bool (flag is an unused parameter.)

PDP10:

  pdp10_ksio.c: Return type from build_dib_tab should be t_stat,
    not t_bool.

PDP11:

  pdp11_cr.c: Assign eof_pending to TRUE (vice 1.)

  pdp11_rq.c: Assign dontchangecapac from Boolean expression.

SAGE:

  m68k_sys.c: Fix sim_load()'s flag parameter type, should be int, not
      t_bool.

VAX:

  vax_sysdev.c: Initialize ka_hltenab, tmr_inst[] to TRUE, FALSE to be
      consistent with t_bool.

  vax_va.c, vax_vc.c, vax4xx_va.c, vax4xx_vc.c: Assign va_input_captured
      from Boolean expression.

  vax780_fload.c: Update rtfile_read() return type to t_bool (not t_stat.)

Author: bscottm

3B2/3b2_mau.h

@@ -186,15 +186,15 @@
 #define MAU_RC_RZ         3            /* Round toward Zero        */
 #endif
 
-#define SFP_SIGN(V)  (((V) >> 31) & 1)
+#define SFP_SIGN(V)  ((((V) >> 31) & 1) != 0)
 #define SFP_EXP(V)   (((V) >> 23) & 0xff)
 #define SFP_FRAC(V)  ((V) & 0x7fffff)
 
-#define DFP_SIGN(V)  (((V) >> 63) & 1)
+#define DFP_SIGN(V)  ((((V) >> 63) & 1) != 0)
 #define DFP_EXP(V)   (((V) >> 52) & 0x7ff)
 #define DFP_FRAC(V)  ((V) & 0xfffffffffffffull)
 
-#define XFP_SIGN(V)  (((V)->sign_exp >> 15) & 1)
+#define XFP_SIGN(V)  ((((V)->sign_exp >> 15) & 1) != 0)
 #define XFP_EXP(V)   ((V)->sign_exp & 0x7fff)
 #define XFP_FRAC(V)  ((V)->frac)
 

AltairZ80/m68k/example/m68kcpu.c

@@ -1047,7 +1047,7 @@ void m68k_set_irq(unsigned int int_level)
 	/* A transition from < 7 to 7 always interrupts (NMI) */
 	/* Note: Level 7 can also level trigger like a normal IRQ */
 	if(old_level != 0x0700 && CPU_INT_LEVEL == 0x0700)
-		m68ki_cpu.nmi_pending = TRUE;
+		m68ki_cpu.nmi_pending = NMI_TRUE;
 }
 
 void m68k_set_virq(unsigned int level, unsigned int active)

AltairZ80/m68k/m68k.h

@@ -38,9 +38,9 @@ extern "C" {
 #define ARRAY_LENGTH(x)         (sizeof(x) / sizeof(x[0]))
 #endif
 
-#ifndef FALSE
-#define FALSE 0
-#define TRUE 1
+#ifndef NMI_FALSE
+#define NMI_FALSE 0
+#define NMI_TRUE 1
 #endif
 
 /* ======================================================================== */

AltairZ80/m68k/m68kcpu.c

@@ -1047,7 +1047,7 @@ void m68k_set_irq(unsigned int int_level)
     /* A transition from < 7 to 7 always interrupts (NMI) */
     /* Note: Level 7 can also level trigger like a normal IRQ */
     if(old_level != 0x0700 && CPU_INT_LEVEL == 0x0700)
-        m68ki_cpu.nmi_pending = TRUE;
+        m68ki_cpu.nmi_pending = NMI_TRUE;
 }
 
 void m68k_set_virq(unsigned int level, unsigned int active)

AltairZ80/m68k/m68kcpu.h

@@ -2136,7 +2136,7 @@ static inline void m68ki_check_interrupts(void)
 {
     if(m68ki_cpu.nmi_pending)
     {
-        m68ki_cpu.nmi_pending = FALSE;
+        m68ki_cpu.nmi_pending = NMI_FALSE;
         m68ki_exception_interrupt(7);
     }
     else if(CPU_INT_LEVEL > FLAG_INT_MASK)

AltairZ80/m68k/softfloat/milieu.h

@@ -38,5 +38,5 @@ these four paragraphs for those parts of this code that are retained.
 /*----------------------------------------------------------------------------
 | Symbolic Boolean literals.
 *----------------------------------------------------------------------------*/
-#define FALSE 0
-#define TRUE 1
+#define NMI_FALSE 0
+#define NMI_TRUE 1

AltairZ80/s100_dazzler.c

@@ -63,10 +63,10 @@
 */
 VID_DISPLAY *daz_vptr = NULL;
 
-static t_bool daz_0e = 0x00;
-static t_bool daz_0f = 0x80;
+static uint8 daz_0e = 0x00;
+static uint8 daz_0f = 0x80;
 static uint32 daz_addr = 0x0000;
-static t_bool daz_frame = 0x3f;
+static uint8 daz_frame = 0x3f;
 static uint8 daz_res = 32;
 static uint16 daz_pages = 1;
 static uint16 daz_window_width = 640;

H316/h316_hi.c

@@ -784,7 +784,7 @@ t_stat hi_attach (UNIT *uptr, CONST char *cptr)
   //    ATTACH HIn llll:w.x.y.z:rrrr - connect via UDP to a remote simh host
   //
   t_stat ret;  char *pfn;  uint16 host = uptr->hline;
-  t_bool fport = sim_switches & SWMASK('P');
+  t_bool fport = ((sim_switches & SWMASK('P')) != 0);
 
   // If we're already attached, then detach ...
   if ((uptr->flags & UNIT_ATT) != 0) detach_unit(uptr);

H316/h316_mi.c

@@ -694,7 +694,7 @@ t_stat mi_attach (UNIT *uptr, CONST char *cptr)
   //    ATTACH MIn llll:w.x.y.z:rrrr - connect via UDP to a remote simh host
   //
   t_stat ret;  char *pfn;  uint16 line = uptr->mline;
-  t_bool fport = sim_switches & SWMASK('P');
+  t_bool fport = ((sim_switches & SWMASK('P')) != 0);
 
   // If we're already attached, then detach ...
   if ((uptr->flags & UNIT_ATT) != 0) detach_unit(uptr);

HP2100/hp2100_defs.h

@@ -740,8 +740,8 @@ typedef enum {                                  /* poll synchronization modes */
 /* Flip-flops */
 
 typedef enum {                                  /* flip-flop values */
-    CLEAR = 0,                                  /*   the flip-flop is clear */
-    SET   = 1                                   /*   the flip-flop is set */
+    CLEAR = FALSE,                              /*   the flip-flop is clear */
+    SET   = TRUE                                /*   the flip-flop is set */
     } FLIP_FLOP;