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authorH. Peter Anvin <hpa@zytor.com>2009-04-23 14:33:26 -0700
committerH. Peter Anvin <hpa@zytor.com>2009-04-23 14:33:26 -0700
commit080bf565b4422c15c944a57f72541b92fa492fc9 (patch)
tree2ae69121e6618003d123099f79e30ffb61640d27
parentafa6e3dec454424863733317ea29ff20a718e277 (diff)
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syslinux.git-080bf565b4422c15c944a57f72541b92fa492fc9.tar.xz
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shuffle_rm: clean up the trampoline generator with macros
Define macros for common constructs to clean up the rm trampoline generator. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--com32/lib/syslinux/shuffle_rm.c81
1 files changed, 50 insertions, 31 deletions
diff --git a/com32/lib/syslinux/shuffle_rm.c b/com32/lib/syslinux/shuffle_rm.c
index 2496b888..5d79cad7 100644
--- a/com32/lib/syslinux/shuffle_rm.c
+++ b/com32/lib/syslinux/shuffle_rm.c
@@ -42,8 +42,37 @@
enum gpr_index { R_AX, R_CX, R_DX, R_BX, R_SP, R_BP, R_SI, R_DI };
enum seg_index { R_ES, R_CS, R_SS, R_DS, R_FS, R_GS };
-#define MOV_TO_SEG(S,R) (0xc08e + ((R) << 8) + ((S) << 11))
-#define MOV_TO_R32(R) (0xb866 + ((R) << 8))
+#define ST8(P,V) \
+ do { \
+ uint8_t *_p = (void *)(P); \
+ *_p++ = (V); \
+ (P) = (void *)_p; \
+ } while (0);
+#define ST16(P,V) \
+ do { \
+ uint16_t *_p = (void *)(P); \
+ *_p++ = (V); \
+ (P) = (void *)_p; \
+ } while (0)
+#define ST32(P,V) \
+ do { \
+ uint32_t *_p = (void *)(P); \
+ *_p++ = (V); \
+ (P) = (void *)_p; \
+ } while (0)
+
+#define MOV_TO_SEG(P,S,R) \
+ ST16(P, 0xc08e + ((R) << 8) + ((S) << 11))
+#define MOV_TO_R16(P,R,V) \
+ do { \
+ ST8(P, 0xb8 + (R)); \
+ ST16(P, V); \
+ } while (0)
+#define MOV_TO_R32(P,R,V) \
+ do { \
+ ST16(P, 0xb866 + ((R) << 8)); \
+ ST32(P, V); \
+ } while (0)
int syslinux_shuffle_boot_rm(struct syslinux_movelist *fraglist,
struct syslinux_memmap *memmap,
@@ -58,6 +87,7 @@ int syslinux_shuffle_boot_rm(struct syslinux_movelist *fraglist,
} *rp;
int i, rv;
uint8_t handoff_code[8+5*5+8*6+1+5], *p;
+ uint16_t off;
struct syslinux_memmap *tmap;
addr_t regstub, stublen;
/* Assign GPRs for each sreg, don't use AX and SP */
@@ -102,46 +132,35 @@ int syslinux_shuffle_boot_rm(struct syslinux_movelist *fraglist,
/* Set up GPRs with segment registers - don't use AX */
for (i = 0; i < 6; i++) {
- if (i != R_CS) {
- p[0] = 0xb8 + gpr_for_seg[i]; /* MOV reg,imm16 */
- *(uint16_t *)(p+1) = rp->seg[i];
- p += 3;
- }
+ if (i != R_CS)
+ MOV_TO_R16(p, gpr_for_seg[i], rp->seg[i]);
}
/* Actual transition to real mode */
- *(uint32_t *)p = 0xeac0220f; /* MOV CR0,EAX; JMP FAR */
- *(uint16_t *)(p+4) = (p-handoff_code)+8; /* Offset */
- *(uint16_t *)(p+6) = regstub >> 4; /* Segment */
- p += 8;
+ ST32(p, 0xeac0220f); /* MOV CR0,EAX; JMP FAR */
+ off = (p-handoff_code)+4;
+ ST16(p, off); /* Offset */
+ ST16(p,regstub >> 4); /* Segment */
/* Load SS and ESP immediately */
- *(uint16_t *)p = MOV_TO_SEG(R_SS, R_BX);
- *(uint16_t *)(p+2) = MOV_TO_R32(R_SP);
- *(uint32_t *)(p+4) = rp->seg[R_SP];
- p += 8;
+ MOV_TO_SEG(p, R_SS, R_BX);
+ MOV_TO_R32(p, R_SP, rp->seg[R_SP]);
/* Load the other segments */
- *(uint16_t *)p = MOV_TO_SEG(R_ES, R_CX);
- p += 2;
- *(uint16_t *)p = MOV_TO_SEG(R_DS, R_BP);
- p += 2;
- *(uint16_t *)p = MOV_TO_SEG(R_FS, R_SI);
- p += 2;
- *(uint16_t *)p = MOV_TO_SEG(R_GS, R_DI);
- p += 2;
+ MOV_TO_SEG(p, R_ES, R_CX);
+ MOV_TO_SEG(p, R_DS, R_BP);
+ MOV_TO_SEG(p, R_FS, R_SI);
+ MOV_TO_SEG(p, R_GS, R_DI);
for (i = 0; i < 8; i++) {
- if (i != R_SP) {
- *(uint16_t *)p = MOV_TO_R32(i); /* MOV r32,imm32 */
- *(uint32_t *)(p+2) = rp->gpr[i];
- p += 6;
- }
+ if (i != R_SP)
+ MOV_TO_R32(p, i, rp->gpr[i]);
}
- *p++ = rp->sti ? 0xfb : 0xfa; /* STI/CLI */
- *p++ = 0xea; /* JMP FAR */
- *(uint32_t *)p = rp->csip;
+ ST8(p, rp->sti ? 0xfb : 0xfa); /* STI/CLI */
+
+ ST8(p, 0xea); /* JMP FAR */
+ ST32(p, rp->csip);
/* Add register-setting stub to shuffle list */
if (syslinux_add_movelist(&fraglist, regstub, (addr_t)handoff_code,