cleanup cg code

update cg documentation

bld/cg/doc/cgref.gml

@@ -213,10 +213,11 @@ Generate code into a use32 segment (versus use16).
 Generate all global and static variable references as an offset
 past EBX.
 .note CGSW_X86_WINDOWS
-Generate windows prolog/epilog sequences for all routines.
+Generate 16-bit Windows prolog/epilog sequences for callbacks and routines.
 .note CGSW_X86_CHEAP_WINDOWS
-Generate windows prolog/epilog sequences assuming that call backs
-functions are defined as __export.
+Generate 16-bit Windows prolog/epilog sequences assuming for callbacks only (cheap).
+.note CGSW_X86_SMART_WINDOWS
+Generate 16-bit Windows optimized prolog/epilog sequences assuming DS==SS (smart).
 .note CGSW_GEN_NO_CALL_RET_TRANSFORM
 Do not change a CALL followed by a RET into a JMP.
 This is used for some older overlay managers that cannot handle a JMP

bld/cg/intel/h/x86swi.h

@@ -2,7 +2,7 @@
 *
 *                            Open Watcom Project
 *
-* Copyright (c) 2002-2022 The Open Watcom Contributors. All Rights Reserved.
+* Copyright (c) 2002-2023 The Open Watcom Contributors. All Rights Reserved.
 *    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
 *
 *  ========================================================================
@@ -42,12 +42,12 @@ CGSW_X86_FLOATING_SS             = 0x00000100,  /* SS selector is floating */
 CGSW_X86_FLOATING_DS             = 0x00000200,  /* DS selector is floating */
 CGSW_X86_USE_32                  = 0x00000400,  /* Generate 32-bit segments */
 CGSW_X86_INDEXED_GLOBALS         = 0x00000800,  /* Position Independent Code (faulty!) */
-CGSW_X86_WINDOWS                 = 0x00001000,  /* Generate Win16 prologs */
-CGSW_X86_CHEAP_WINDOWS           = 0x00002000,  /* Cheap Win16 prologs */
-CGSW_X86_CONST_IN_CODE           = 0x00004000,  /* FP consts in code segment */
-CGSW_X86_NEED_STACK_FRAME        = 0x00008000,  /* Always generate stack frame */
-CGSW_X86_LOAD_DS_DIRECTLY        = 0x00010000,  /* No runtime call to load DS */
-CGSW_X86_SMART_WINDOWS           = 0x00020000,  /* Smart Win16 prolog (DS==SS) */
+CGSW_X86_WINDOWS                 = 0x00001000,  /* Generate Win16 prologs for callbacks and functions */
+CGSW_X86_CHEAP_WINDOWS           = 0x00002000,  /* Generate Win16 prologs (cheap), only callbacks */
+CGSW_X86_SMART_WINDOWS           = 0x00004000,  /* Generate Win16 prologs (smart) DS==SS */
+CGSW_X86_CONST_IN_CODE           = 0x00008000,  /* FP consts in code segment */
+CGSW_X86_NEED_STACK_FRAME        = 0x00010000,  /* Always generate stack frame */
+CGSW_X86_LOAD_DS_DIRECTLY        = 0x00020000,  /* No runtime call to load DS */
 CGSW_X86_P5_PROFILING            = 0x00040000,  /* Pentium RDTSC profiling (-et) */
 CGSW_X86_P5_DIVIDE_CHECK         = 0x00080000,  /* Check for bad Pentium FDIV */
 CGSW_X86_GENERIC_TLS             = 0x00100000,  /* TLS code not NT specific (unused?) */