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Diffstat (limited to 'utils.h')
| -rw-r--r-- | utils.h | 94 |
1 files changed, 94 insertions, 0 deletions
@@ -0,0 +1,94 @@ +#ifndef UTILS_H +#define UTILS_H + +#include <stdint.h> + +#define ABS(x) (((x) < 0) ? -(x) : (x)) + +#define MIN(a,b) (((a) < (b)) ? (a) : (b)) +#define MAX(a,b) (((a) > (b)) ? (a) : (b)) + +#define BOUND(x,a,b) ( MIN(b, MAX(a, x)) ) + +static inline void breakpoint(void); +#pragma aux breakpoint = 0xcd 0x03; + +static inline void cli(void); +#pragma aux cli = "cli" + +static inline void sti(void); +#pragma aux sti = "sti" + +/** Map x linearly from range [0, srcmax] to [0, dstmax]. + * Equivalent of (x * dstmax) / srcmax but with 32-bit unsigned precision. */ +static unsigned scaleu(unsigned x, unsigned srcmax, unsigned dstmax); +#pragma aux scaleu = \ + "mul cx" /* dx:ax = x * dstmax */\ + "div bx" /* ax = dx:ax / srcmax */\ + __parm [ax] [bx] [cx] \ + __value [ax] \ + __modify [ax cx dx] + +/** Map x linearly from range [0, srcmax] to [0, dstmax]. + * Equivalent of (x * dstmax) / srcmax but with 32-bit signed precision. + * Division remainder is returned in rem, which should be reused + * in future calls to reduce rounding error. */ +static int scalei_rem(int x, int srcmax, int dstmax, short *rem); +#pragma aux scalei_rem = \ + "imul cx" /* dx:ax = x * dstmax */ \ + "add ax, [si]" /* ax += *rem */ \ + "adc dx, 0" /* dx += 1 if carry */ \ + "idiv bx" /* ax = dx:ax / srcmax, dx = new remainder */ \ + "mov [si], dx" /* store the new remainder */ \ + __parm [ax] [bx] [cx] [si] \ + __value [ax] \ + __modify [ax cx dx] + +static void bzero(void __far *buf, unsigned int size); +#pragma aux bzero = \ + "cld" \ + "mov ax, 0" \ + "rep stos byte ptr es:[di]" \ + __parm [es di] [cx] \ + __modify [ax] + +static void nfmemcpy(void __far *dst, const void *src, unsigned int size); +#pragma aux nfmemcpy = \ + "cld" \ + "rep movs byte ptr es:[di], byte ptr ds:[si]" \ + __parm [es di] [si] [cx] \ + __modify [cx si di] + +static void fnmemcpy(void *dst, const void __far *src, unsigned int size); +#pragma aux fnmemcpy = \ + "cld" \ + "push gs" \ + "mov ax, es" \ + "mov gs, ax" /* gs is now the src segment */ \ + "mov ax, ds" \ + "mov es, ax" /* es is now ds, the dst segment */ \ + "rep movs byte ptr es:[di], byte ptr gs:[si]" \ + "pop gs" \ + __parm [di] [es si] [cx] \ + __modify [ax cx si di es] + +static void ffmemcpy(void __far *dst, const void __far *src, unsigned int size); +#pragma aux ffmemcpy = \ + "cld" \ + "push gs" \ + "mov gs, ax" \ + "rep movs byte ptr es:[di], byte ptr gs:[si]" \ + "pop gs" \ + __parm [es di] [gs si] [cx] \ + __modify [cx si di] + +static void nnmemcpy(void *dst, const void *src, unsigned int size); +#pragma aux nnmemcpy = \ + "cld" \ + "mov ax, ds" \ + "mov es, ax" /* es is now ds, the src+dst segment */ \ + "rep movs byte ptr es:[di], byte ptr ds:[si]" \ + __parm [di] [si] [cx] \ + __modify [cx si di es] + +#endif |